Enzymes are biological catalysts that facilitate biochemical reactions in horses by lowering the activation energy required for these processes. They are involved in various physiological functions, including digestion, metabolism, and cellular repair. Common enzymes in equine biology include amylase, lipase, and lactate dehydrogenase, each playing a specific role in the breakdown of nutrients and energy production. The activity and concentration of these enzymes can vary in response to different physiological and pathological conditions, serving as potential indicators in veterinary diagnostics. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of enzymes in equine health.
Gill J, Jakubów K, Kompanowska-Jezierska E, Kott A, Szumska D.In 34 pure breed Arabian horses divided into four groups (Gr. I--10 pregnant mares, Gr. II--7 barren mares, Gr. III--10 foals born in 1981, Gr. IV--7 foals born in 1982) seasonal changes in total blood serum protein, its electrophoretic fractions and the activity of AspAT and AlAT were studied. Seasonal cyclicity was found in all groups in the amount of total serum proteins, and alpha 2- and beta 1-globulin fractions. Cyclicity was found in the level of albumin and activity of AspAT in three groups, not Gr. II, and in gamma-globulin, not Gr. IV. beta 2-globulin and AlAT cyclicity was found in ...
Dubin A, Potempa J, Silberring J.Horse leucocyte neutral proteinase inhibitor reacts with all tested elastases at the molar ratios of 1:1 and yielding stable complexes (Ki = 10(-10) M). The above reactions are very rapid, characterized by the high values of association rate constant kon = 10(7) M-1s-1.
Magnuson NS, Perryman LE, Suttle DP, Robinson JL, Mason PH, Marta KM.In an attempt to determine the metabolic defect causing severe combined immunodeficiency (SCID) in horses in which altered purine metabolism has been observed, various parameters of purine and pyrimidine metabolism were evaluated. The activities of nine purine enzymes (adenosine kinase, purine nucleoside phosphorylase, deoxyadenosine kinase, deoxycytidine kinase, 5'-nucleotidase, AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase, and adenine phosphoribosyl transferase were measured in fibroblasts. All activities determined for SCID horses were normal. Uptake of 10 microM adenosine...
Adams R, McClure JJ, Gossett KA, Koonce KL, Ezigbo C.gamma-Glutamyltranspeptidase (GGT) activity in equine urine was measured, using an assay developed for use with serum and was found to be reproducible. The GGT activity was measured in samples prepared by serial dilution of exogenous GGT with equine urine, and the activity was determined to be linear between 21 IU/L and 407 IU/L. The behavior of exogenously added GGT was compared in equine serum and urine. The enzyme behaved similarly in both fluids. The GGT activity was measured in serum and urine samples after storage at -20, 4, and 25 C for 24 and/or 72 hours. Enzyme activity decreased afte...
Matoba H, Allen JR, Bayly WM, Oakley CR, Gollnick PD.Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu2+ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indicati...
Bertram TA.Differences in neutrophil morphology between various species of domestic animals are evident when morphometric techniques are used. Morphometric analysis can be coupled with functional assays of degranulation to demonstrate changes in granule volume after neutrophil activation (Bertram and Jensen, 1984). Morphometric and functional analysis of the neutrophil can also be used to evaluate the response of neutrophils to infectious agents (Coignoul et al., 1984a). Comparison of these assays between animal species may provide insight into the susceptibility of animals to various microbial pathogens...
Maly IP, Sasse D.Microquantitative measurements of ADH-activity were carried out on the livers of male and female rats, guinea-pigs and horses (two geldings and a mare). Lyophilized cryostat sections of liver parenchyma were microdissected the whole way along the sinusoidal length from the terminal afferent vessels to the terminal efferent venule. ADH activity in samples of about 50-150 ng was measured in a microbiochemical assay using the oil-well technique without enzymatic cycling, by direct luminometric determination of NADH. On the basis of the single measurements, mean values of total hepatic ADH activit...
Betton JM, Desmadril M, Mitraki A, Yon JM.The unfolding-refolding transition of horse muscle phosphoglycerate kinase induced by guanidine hydrochloride was studied under equilibrium conditions using four different signals: fluorescence intensity at 336 nm, UV difference absorbance at 286 and 292 nm, ellipticity at 220 nm, and enzyme activity. From the following arguments, we found that the process deviates from a two-state model and intermediates are significantly populated even at equilibrium: (1) the noncoincidence of the transition curves and (2) the asymmetry of the transition curve obtained from CD measurements. From these differ...
Harkiss GD.An isotype-specific microELISA is presented for the measurement of antibodies to equine antithymocyte globulin in human heart transplant recipients. The assay conditions were optimized and evaluated in serial samples from 40 patients receiving a cardiac allograft. The results demonstrate that despite steroid immunosuppression and T cell cytopenia the majority of patients receiving antithymocyte globulin develop significant antibody responses, with some producing very high titres. IgM and IgG isotypes tended to predominate, with peak antibody responses occurring during the second and third week...
Söylemez Z, Ozer I.The inhibition of horse plasma cholinesterase by propranolol showed characteristics which depended upon the identity of the substrate used. With butyrylthiocholine as substrate, the inhibition showed a first-order dependence on inhibitor concentration, and was characterized by a Ki of 8 microM (pH 7.4, 20 degrees C). With p-nitrophenylbutyrate as substrate, a biphasic v-1 versus [I] relationship was obtained. The biphasic curve could be resolved into two components, with apparent Ki's of 9 microM and 1.3 mM. Use of butyrylthiocholine as alternative substrate resulted in partial inhibition of p...
Blanchard DB, Leid RW.Bovine and equine factor D were purified to apparent homogeneity as evidenced by a single protein staining band on 7.5-17.5% SDS-PAGE slab gels under both reducing and non-reducing conditions. An apparent mol. wt of 15,000 for bovine D and 22,500 for equine D were noted after SDS-PAGE gel analysis of both reduced and non-reduced preparations. A single polypeptide chain for both proteins was evidenced by the lack of any change in the electrophoretic mobility under each of these conditions. The bovine and equine D were enriched 3347- and 9447-fold, with a 20 and 29% yield of hemolytic activity, ...
Makhaeva GF, Shataeva GA, Iankovskaia VL, Fetisov VI, Loshadkin NA.The interaction of human erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase and rat liver carboxylesterase with insecticides (RO)2P(O)SCH(COOEt)SP(O)(OR)2 (I) and (RO)2P(O)SCH(COOEt)OP(S)(OR)2 (II) was studied. The type I and II compounds were not hydrolyzed by carboxylesterase and inhibited the esterases irreversibly. A complex pattern of inhibition of acetylcholinesterase and butyrylcholinesterase by these compounds was caused by kinetically-manifested formation of an enzyme-inhibitor complex. The compounds I and II were more selective towards butyrylcholinesterase than towa...
Corda M, Pellegrini M, Rinaldi A.Diamine oxidase was prepared from horse kidney by a procedure involving heat denaturation at 50 degrees C, ammonium sulfate fractionation, chromatography on hydroxyapatite and on G-200 Sephadex columns. This procedure gave about 1000 fold purification over the crude kidney cortex homogenate. The enzyme preparations thus obtained are stable only at high ionic strength. The effect on enzyme activity of salt concentration and various stabilizing agents have been investigated. The horse kidney diamine oxidase is irreversibly inhibited by carbonyl reagents and shows substrate specificity quite simi...
Martini F, Angelaccio S, Barra D, Doonan S, Bossa F.Cytosolic aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) from horse heart has five cysteine residues, two of which can be titrated with 5,5'-dithiobis(2-nitrobenzoid acid) in the native enzyme with no impairment of catalytic activity. The rate of modification is unaffected by the presence of substrates. Reaction with N-ethylmaleimide leads to loss of catalytic activity, the rate of inactivation being increased by the presence of substrates. Peptides containing 361 amino-acid residues (about 88% of the total number in the protein) have been isolated and ali...
Robinson-Steiner AM, Beebe SJ, Rannels SR, Corbin JD.Excluding autophosphorylated species, at least six forms of the regulatory subunit of type II cAMP-dependent protein kinase (RII) from various mammalian tissues were identified by sodium dodecyl sulfate (SDS) gel electrophoresis of purified samples and of crude preparations photoaffinity labeled with 8-azido[32P] cAMP and by gel filtration. After autophosphorylation some heart RII forms termed type IIA (bovine, porcine, equine, and dog) shifted to a more slowly migrating band on SDS gels while others termed type IIB (rat, guinea pig, rabbit, and monkey) did not detectably shift. Both subclasse...
Eley CG, Ragg E, Moore GR.The reduction of horse and Candida krusei cytochromes c by ferrocyanide has been studied by 1H NMR spectroscopy and the reaction found to involve a precursor complex of ferrocyanide bound to ferricytochrome c (pH* 7.4, 2H2O, I = 0.12, and 25 degrees C). The electron transfer rate constants for the reduction of the two ferricytochromes by associated ferrocyanide were found to be the same at 780 +/- 80 sec-1 but the association constants for binding of ferrocyanide to ferricytochrome c were significantly different: horse, 90 +/- 20 M-1 and Candida, 285 +/- 30 M-1. The different association const...
Myer YP, Kumar S.The ascorbate reduction of horse heart ferricytochrome c in 0.05 M phosphate + 0.25 M sodium sulfate, at pH 7.3, as a function of temperature, 12-36 degrees C, and at alkaline pH 8.4 using stopped flow technique has been examined. The data have been analyzed in terms of a two-step mechanism, binding followed by reduction (Myer, Y.P., Thallam, K.K., and Pande, A. (1980) J. Biol. Chem. 255, 9666-9673). At neutral pH and up to about 26 degrees C, the first order reduction constant is independent of temperature, i.e. with zero or near-zero activation energy. At higher temperatures, it becomes temp...
Gonchar MV, Lavrenova GI, Rudenskaia GN, Gaĭda AV, Stepanov VM.Using ion-exchange and affinity chromatography and isoelectrofocusing, eight forms of pepsin with pI 1.6, 1.8, 2.1, 2.3, 2.6, 2.8, 3.2 and 3.6, were isolated from horse gastric juice. The molecular weights, amino acid composition, N-terminal sequence and functional activity of these multiple forms were determined. Partial primary structure of tryptic peptides of pepsin with pI 2.3 was investigated. The analyzed partial sequences of the forms with pI 1.8, 2.1, 2.3, and 2.6 have identical structures which differ from the amino acid sequence of pepsin with pI 3.2 by four substituents. In terms of...
Steiss JE, Forsyth G.The effect of needle electromyography (EMG) on serum creatine kinase (CK) activity was determined, using clinically normal dogs (males and females; n = 8) and horses (females; n = 8). All animals appeared normal on EMG evaluation. Serum CK was measured before and 4, 24, and 48 hours after EMG. Except for a single 24-hour sample in a dog, the animals did not have abnormally increased serum CK activity after EMG. For dogs and horses, mean values were increased, but within normal range at 4 and 24 hours and returned to base-line values by 48 hours after EMG. For dogs, but not for horses, these CK...
Chang CK, Ward B, Ebina S.Carbon monoxide- and oxygen-binding rates and affinities were measured for horse heart myoglobins reconstituted with synthetic hemes lacking peripheral methyl and vinyl groups. There is an apparent correlation between heme size and ligand specificity, i.e. larger m values (ratios of CO vs O2 association rates, l'/k') with smaller hemes. However, this correlation broke down with the most dealkylated heme. This is interpreted as resulting from protein conformational changes altering the steric crowdedness at the O2-binding site. Spectral properties and autoxidation rates also corroborate this vi...
Rice DW, Blake CC.Crystals of horse muscle 3-phosphoglycerate kinase have been grown in the presence of a wide variety of substrates using either potassium tartrate or polyethylene glycol as a precipitant. In those grown from polyethylene glycol, two related crystal forms have been obtained by varying the nature of the substrates present in the crystallization medium. In order to obtain one of these forms, form B, the presence of the substrate 3-phosphoglycerate appears to be essential. The two crystal forms are not interconvertible by simple diffusion experiments and the crystals grown in the absence of 3-phos...
Essén-Gustavsson B, Karlström K, Lindholm A.Venous blood samples and middle gluteal muscle biopsies were obtained from 21 horses taking part in 100 km or 50 km endurance rides. Group A consisted of seven horses competing over 100 km (four horses completed the ride). Group B consisted of the six horses that were among the 10 best over 50 km while the other eight horses of Group C completed 50 km at a slower speed. Blood lactate, glycerol and creatine kinase increased in all groups while aspartate aminotransferase levels were higher only in Group A. No changes was found in blood glucose in Groups B and C while horses in Group A had lower ...
Higgins AJ, Lees P.Arachidonic acid is a polyunsaturated fatty acid covalently bound in esterified form in the cell membranes of most body cells. Following irritation or injury, arachidonic acid is released and oxygenated by enzyme systems leading to the formation of an important group of inflammatory mediators, the eicosanoids. It is now recognised that eicosanoid release is fundamental to the inflammatory process. For example, the prostaglandins and other prostanoids, products of the cyclooxygenase enzyme pathway, have potent inflammatory properties and prostaglandin E2 is readily detectable in equine acute in...
Szwarocka-Priebe T, Gill J.Twenty Thoroughbred 3 year old horses (10 stallions and 10 mares), trained and raced at the Warsaw Race-Course were studied from March through November. Blood was taken approximately every 8 weeks to determine the activities of aspartate and alanine transaminases, acid and alkaline phosphatases and aldolase. It was observed that the activities of aspartate aminotransferase and alkaline phosphatase reached their maxima in July and alanine transaminase in May. The activities of acid phosphatase and aldolase showed their minima in July. Comparing these data with the literature it was noted that t...
Pellegrini A, Hägeli G, Fretz D, von Fellenberg R.An electrophoretic procedure for the qualitative and quantitative assay of protein protease inhibitors is reported. This assay is particularly suited for investigations of crude biological materials when specific antisera are not available. The supporting medium consists of agarose into which denatured fibrinogen is incorporated as the substrate for proteases. The processing then is divided into two steps: (1) electrophoretic resolution of the inhibitor containing material and (2) detection of the inhibitor bands through their protease inhibiting activity. The inhibitor position is thus made v...
Jabusch JR, Deutsch HF.The amino acid sequence of the high-activity equine erythrocyte carbonic anhydrase (CA-II) has been determined. Two different N-termini are noted, the C1 form having an N-acetyl-serine and the C2 form an N-acetyl-threonine. The sequence of the equine enzyme is most homologous to the human CA-II isozyme, with 224 of the 259 residues being identical.
Dubin A, Potempa J, Silberring J.alpha 2-macroglobulin was isolated by polyethylene glycol precipitation, gel filtration on Sephacryl S-300 and DE-52 cellulose chromatography, with 20% yield. The preparation obtained was homogenous as tested by biochemical and immunological criteria. Its molecular mass was estimated at 800,000, comprising of four identical subunits. The isoelectric point of our preparation was 4.8 and two molecules of serine proteinases per 1 molecule of inhibitor were bound.
Kovár J.Single biochemical analyses can be used for the diagnosis of animal diseases only with the knowledge of the effects that may distort the single result. The study of the repeatability of analyses is described in the four basic enzymes (AST, ALP, GMT, LD), which are most frequently used for diagnosis. The experiment was conducted in a group of ten Kladrub mares. Six blood samples were taken from each of the mares within ten days. The measured values were subjected to statistical processing and repeatability coefficients (r op) were calculated. All the r op values were high (ALP--0.96, LD--0.93, ...
Bijault C, Dehennin L.Steroid 21-hydroxylase activity of the microsome-enriched fraction of follicular linings from equine ovaries has been demonstrated by gas chromatography-mass spectrometry. The 21-hydroxylated metabolites were quantified by isotope dilution with deuterated analogues. The two most abundant potential substrates for follicular steroid 21-hydroxylase, progesterone (P) and 17-hydroxyprogesterone (17OHP), were converted respectively to 11-deoxycorticosterone (DOC) and 11-deoxycortisol with corresponding apparent specific activities of 308 and 24 pmol/mg protein/h and apparent Km values of 1.1 and 6.4...
Rouge M, Elkhatib R, Delalande C, Cognié J, Reigner F, Barriere P, Deleuze S, Cousty M, Legendre F, Galera P, Hanoux V, Bouraima-Lelong H.Although vitamin D acts in various biological processes, it plays a critical role in the maintenance of bone health, and regulates calcium homeostasis. In humans and rodents, the main tissues involved in vitamin D metabolism are the liver and the kidneys, however it has been shown that the testis has strongly participated in its bioactivation. Indeed, in these different species, enzymes metabolizing vitamin D (CYP27A1, CYP27B1 and CYP2R1) have been demonstrated in this tissue. Moreover, men with hypogonadism have shown a decrease in circulating levels of vitamin D. In equine species, the castr...
Nebbia C, Dacasto M, Carletti M.Little is known about the effects of aging on the hepatic drug metabolizing capacity of horses despite the relatively long lifespan characterizing this species. A wide array of cytochrome P450 (CYP)-dependent monooxygenases, carboxylesterases and transferases were assayed in liver microsomes from 50 female horses in an age range between less than 1 year to over 12 years. Rather unexpectedly, both the CYP content and the activity of NADPH cytochrome c reductase rose as a function of age. Accordingly, a general increasing trend was recorded in the rate of the in vitro metabolism of the substrate...
Flood PF, Marrable AW.The distribution of several hydroxysteroid dehydrogenases (HSD) was examined in a variety of equine placental and fetal tissues. The main points of interest were: (a) the lack of dehydrogenase activity in the gonad, (b) the appearance of a variety of HSDs in the trophoblast as early as 13 days of gestation, (c) the histochemical similarity between the cells of the trophoblast and the endometrial cup, and (d) the restriction of the strong endometrial 17beta-HSD reaction to those parts of the uterine epithelium directly apposed to the trophoblast.
Jagodzinski PW, Funk GF, Peticolas WL.The nature of the binding of aromatic aldehyde and aromatic alcohol substrates to the catalytic zinc of equine liver alcohol dehydrogenase has been studied by using resonance-enhanced Raman spectroscopy. When an excess of both enzyme and coenzyme to substrate is used, a stable ternary chemical intermediate is formed between liver alcohol dehydrogenase and the reduced coenzyme, nicotinamide adenine dinucleotide, and the aldehyde, p-(dimethylamino)benzaldehyde, in the pH range 8.5-0.6. Resonance-enhanced Raman spectra clearly show that this same intermediate is formed between the excess enzyme, ...
Sandbaumhüter FA, Gittel C, Larenza-Menzies MP, Theurillat R, Thormann W, Braun C.The enantioselectivity of the pharmacokinetics of methadone was investigated in anesthetized Shetland ponies after a single intravenous (0.5 mg/kg methadone hydrochloride; n = 6) or constant rate infusion (0.25 mg/kg bolus followed by 0.25 mg/kg/h methadone hydrochloride; n = 3) administration of racemic methadone. Plasma concentrations of l-methadone and d-methadone and their major metabolites, l- and d-2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), respectively, were analyzed by CE with highly sulfated γ-cyclodextrin as chiral selector and electrokinetic analyte injection from...
de Haas GH, Dijkman R, Lugtigheid RB, Dekker N, Van den Berg L, Egmond MR, Verheij HM.The inhibitory power (Z) of a number of (R)-1-alkyl-2-acylamino phospholipid analogues was determined for three mammalian phospholipases A2 from pig, ox and horse pancreas. All three enzymes display a clear preference for anionic (phosphoglycol) inhibitors over the zwitterionic (phosphocholine) derivatives; this effect is most pronounced for the bovine enzyme. Upon variation of the 1-alkyl chain length, the bovine and equine phospholipases, like the porcine enzyme in previous studies, show an optimum in Z for a six-carbon alkyl group. The introduction of a double bond in the 2-acylamino group ...
Douglas HF, Southwood LL, Meyer-Ficca ML, Hart SK, Meyer RG.To evaluate the poly (ADP-ribose) polymerase-1 (PARP1) enzyme and its inhibition in horses and explore its potential as a novel therapeutic target for equine intestinal ischemia-reperfusion injury by (1) identifying poly (ADP-ribose) (PAR) as an indication of PARP1 activation in equine cells using available immunoblot analytical techniques, (2) inducing PARP1 activation in an in vitro oxidative DNA damage model, (3) and demonstrating the inhibition of PARP1 in equine cells using commercially available PARP1 inhibitors. Methods: Experimental study. Methods: Blood samples were collected from sys...
Meijer AE, van den Hoven R.In this communication, the results of a histochemical and biochemical enzyme study on gluteus medius muscle of horses, sensitive to exertional myopathy, during attacks of rhabdomyolysis are presented. For the biochemical study the biopsy specimens investigated were selected by means of histological and enzyme histochemical staining methods. Dissected specimens were used which contained groups of muscle fibres with a high or low activity of glucose-6-phosphate dehydrogenase. The activity of glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, glutathione reductase, glutathione per...
Ueki M, Takeshita H, Fujihara J, Ueta G, Nakajima T, Kominato Y, Kishi K, Iida R, Yasuda T.Equine (Equus caballus) deoxyribonuclease I (DNase I) was purified from the parotid gland, and its 1295-bp cDNA was cloned. The mature equine DNase I protein consisted of 260 amino acid residues. The enzymatic properties and structural aspects of the equine enzyme were closely similar to those of other mammalian DNases I. Mammalian DNases I are classified into three types--pancreatic, parotid and pancreatic-parotid-based on their tissue distribution; as equine DNase I showed the highest activity in the parotid gland, it was confirmed to be of the parotid-type. Comparison of the susceptibility ...
Mouithys-Mickalad A, Storms N, Franck T, Ceusters J, de la Rebière de Pouyade G, Deby-Dupont G, Serteyn D.Experimental laminitis, characterized by a failure of the dermal-epidermal interface of the foot, can be induced in horses by the oral administration of a black walnut extract (BWE). In the early phase of this severe and painful disease, an activation of neutrophil occurs, with the release of myeloperoxidase (MPO), a pro-oxidant enzyme of neutrophils, in plasma, skin, and laminar tissue. Juglone, a naphthoquinone derivative endowed with redox properties, is found in walnuts and has been incriminated in this neutrophil activation. We report for the first time the inhibitory activity of juglone ...
Patterson SD, Bell K.The carbohydrate side chains of the major plasma serpins of the horse and wallaby have been characterized by lectin analyses of protein blots from two-dimensional gels using the major human plasma serpin, alpha 1-protease inhibitor, as a control. Eight lectins were used in the characterization in conjunction with enzymatic deglycosylation of complex and high mannose side chains, chemical desialylation and defucosylation, and one round of 'Smith degradation', all being performed on the nitrocellulose blots. Assuming a standard complex side chain structure, the results of the 21 lectin/treatment...
Mancheño JM, Jayne S, Kerfelec B, Chapus C, Crenon I, Hermoso JA.Horse pancreatic lipase-related proteins PLRP1 and PLRP2 are produced by the pancreas together with pancreatic lipase (PL). Sequence-comparison analyses reveal that the three proteins possess the same two-domain organization: an N-terminal catalytic domain and a C-terminal domain, which in PL is involved in colipase binding. Nevertheless, despite the high level of sequence identity found, they exhibit distinct enzymatic properties. The intrinsic sensitivity of the peptide bond between Ser245 and Thr246 within the flap region of PLRP2 to proteolytic cleavage probably complicates PLRP2 crystalli...
Sandbaumhüter FA, Theurillat R, Bettschart-Wolfensberger R, Thormann W.The combination of ketamine and an α -receptor agonist is often used in veterinary medicine. Four different α -receptor agonists, medetomidine, detomidine, xylazine, and romifidine, which differ in their chemical structure and thus in selectivity for the α -receptor and in the sedative and analgesic potency, are typically employed during surgery of equines. Recovery following anesthesia with ketamine and an α -receptor agonist is dependent on the α -receptor agonist. This prompted us to investigate (i) the inhibition characteristics for the N-demethylation of ketamine to norketamine and (...
Valberg SJ, Williams ZJ, Finno CJ, Schultz A, Velez-Irizarry D, Henry ML, Gardner K, Petersen JL.Both type 1 (PSSM1) and type 2 polysaccharide storage myopathy (PSSM2) are characterised by aggregates of abnormal polysaccharide in skeletal muscle. Whereas the genetic basis for PSSM1 is known (R309H GYS1), the cause of PSSM2 in Quarter Horses (PSSM2-QH) is unknown and glycogen concentrations not defined. Objective: To characterise the histopathological and biochemical features of PSSM2-QH and determine if an associated monogenic variant exists in genes known to cause glycogenosis. Methods: Retrospective case control. Methods: Sixty-four PSSM2-QH, 30 PSSM1-QH and 185 control-QH were identifi...
Moslemi S, Seralini GE.In order to approach the detailed structure-function relationships of aromatase, we studied the inhibitory and inactivatory potencies of several steroidal androstenedione analogues (1: 4-hydroxyandrostenedione, 2: 4-acetoxyandrostenedione and 3: 7 alpha-(4'-amino)phenylthio-4-androstene-3, 17-dione) and non-steroidal imidazole derivatives (4: ketoconazole, 5: miconazole and 6: fadrozole) on equine aromatase in placental microsomes, a well established mammalian model. Human placental microsomes and the purified enzyme from equine testis were also used to compare inhibition by 1 and 2. In equine...
Ellison RS, Jacobs RM.This study was undertaken to ascertain if the isoelectric focusing pattern of serum alkaline phosphatase (AP) from sick horses with high activity is useful for determining its tissue origin. The effect of oral prednisolone and phenylbutazone therapy on this enzyme in healthy horses was also investigated. The sick horses were divided into three groups: hepatic, intestinal and miscellaneous. All sera had approximately thirteen bands of AP activity when focused on agarose gels with a pH gradient of 3.5 to 9.5. All the horses in the liver disease group had greater than 65% of enzyme activity in ba...
Minguet G, de la Rebière G, Franck T, Joris J, Serteyn D, Sandersen C.To investigate the effects of the volatile anaesthetic sevoflurane on the release of total and active myeloperoxidase (MPO) by non-stimulated and stimulated polymorphonuclear neutrophils (PMNs) in whole blood from healthy horses. Methods: In vitro experimental study. Methods: Adult healthy horses. Methods: Samples of whole venous blood were collected and incubated in air or in air plus 2.3% or 4.6% sevoflurane for 1 hour. PMNs were stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP), with a combination of cytochalasin B (CB) and fMLP or with phorbol myristate acetate (PMA). Total an...
Hatzipanagiotou A, Rieland E, Enbergs H.It was the aim of this project to investigate the changes of the lysozyme activity in the milk of mares during the lactation period. Further on the influence of race, date of conception and foaling, age and number of lactations on the lysozyme activities in milk was analysed. Milk samples were collected from 44 mares (trotters, warmblood, quarter horses) from eight farms between the 1st and 90th day p. p. The activity of the lysozyme was measured by a turbidometric method. Summarizing the following results are obtained: Lysozyme activities in mare milk of the 1st and 3rd day p. p. were higher ...
Forsman C, Jonsson BH, Lindskog S.The 250 MHz 1H-NMR spectrum of horse carbonic anhydrase I (or B) (carbonate hydro-lyase, EC 4.2.1.1) was measured as a function of pH under various conditions. Eight resonances corresponding to histidine C-2 protons and four resonances corresponding to histidine C-4 protons were identified and assigned to individual histidine residues in the enzyme molecule. Substantial similarities between horse and human carbonic anhydrases I were demonstrated. While the human enzyme has three titratable histidine residues in its active site, the horse enzyme has only two, His-67 in the human enzyme being re...
Wahdati A, Lindner A, Sommer H.The influence of temperature and duration of storage on glutathione peroxidase (GSH-Px) activity in plasma and whole blood samples of horses was investigated. Furthermore the relationships between the GSH-Px activities in plasma and whole blood as well as the GSH-Px values related to hematocrit and the hemoglobin content of the blood samples of 93 different horses were calculated. At 20-22 degrees C, the GSH-Px activity in plasma and whole blood samples remained stable over at least three days while it was reduced by 38% and 65% after 2 and 3 days, if the whole blood samples were kept stored a...
Ferguson EW, Bernier LL, Shaughness GP, Boucher JH.Fourteen horses were studied during a 157-km endurance ride. Two humans who ran the 157 km were also evaluated at the finish. Fibrin monomer samples were examined by two-dimensional gel electrophoresis and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Two major species of horse Beta-chain with higher molecular weights and different isoelectric mobilities than human beta-chain were observed. Horse alpha-chains had higher molecular weights than human alpha-chains but similar alpha-chain heterogeneities. Mean euglobulin lysis time (ELT) in the horses was accelerated to similar levels...
Ramponi G, Manao G, Camici G, White GF.It has been shown that horse muscle acylphosphatase is inhibited by pyridoxal 5'-phosphate and that the inhibition is pH dependent, reversible and competitive with respect to substrate binding. Spectral analysis on the EI complex demonstrates the presence of a Schiff base. Reduction of the pyridoxal 5'-phosphate-inhibited enzyme with sodium borohydride, followed by amino acid analysis, produces a diminution of the free lysine peak and the appearance of a new peak corresponding to epsilon-pyridoxyllysine. The results suggest that there is at least one NH2-lysyl residue of horse muscle acylphosp...
Vermeer C, Ulrich M.The presence of vitamin K-dependent carboxylase is demonstrated in the microsomal fraction of horse liver, spleen and kidney. The carboxylating enzyme systems in the spleen and in the kidney are susceptible to warfarin in a similar way as is carboxylase from the liver. It is concluded, that during the administration of vitamin K-antagonists (anticoagulation therapy) carboxylase in all these tissues is inhibited. Since most probably the majority of the reaction products of spleen and kidney carboxylase are no clotting factors, the inhibition of their production is a side-effect of the anticoagu...
Current drug metabolismDecember 19, 2020
Volume 22, Issue 3 215-223 doi: 10.2174/1389200221666201217141025
Hu SX, Ernst K, Benner CP, Feenstra KL.Pharmacokinetic and pharmacodynamic assessment of ester-containing drugs can be impacted by hydrolysis of the drugs in plasma samples post blood collection. The impact is different in the plasma of different species. Objective: This study evaluated the stability of a prodrug, ketoprofen methylester (KME), in commercially purchased and freshly collected plasma of mouse, rat, dog, cat, pig, sheep, cattle and horse. Methods: KME hydrolysis was determined following its incubation in commercially purchased and freshly collected plasma of those species. Different esterase inhibitors were evaluated f...
Bastos HB, Kretzmann NA, Santos GO, Esmeraldino AT, Rechsteiner SF, Mattos RC, Neves AP.The period from the emergence of a dominant follicle until its formation requires tissue remodeling. Enzymes promoting collagen lysis, such as matrix metalloproteinases (MMPs), are fundamental for the process of extracellular matrix remodeling, which allows changes in ovarian tissue architecture during follicular growth. It has been suggested that the production of these enzymes may be affected by the rise in circulating concentrations of LH, which acts on the ovarian surface epithelium (OSE). The aim of this study was to determine the expression of MMP-1, MMP-2, and LH receptor (LHR) in the o...
Linn-Peirano SC, Hepworth-Warren K, Kinsella H, Diaz-Campos D, Brenseke BM, Cianciolo RE, Schroeder E, Schreeg ME.Equine ingesta-associated choledocholithiasis is a rare cause of morbidity and mortality. We describe here the clinical, gross, histologic, and microbiologic features of this condition in 2 horses and compare the features to 2 previous cases. Case 1 was a 4-y-old Thoroughbred mare with colic. Case 2 was an 18-y-old American Paint Horse mare with colic, chronic weight loss, and inappropriate mentation. Both had elevated biochemical markers of hepatocellular injury and cholestasis and were euthanized given a poor prognosis. Case 1 had a well-formed 5-cm choledocholith surrounding a piece of hay,...
Combarnous Y, Salesse R, Garnier J.Pregnant mare serum gonadotropin exhibits a dissociation at acid pH as shown by the drop of s20,w values from 3.52 S at pH 8.1 to 2.52 S at pH 2.0. The dissociation is accompanied by an absorbance change with a maximum at 287 nm and a parallel loss of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) activities as followed by radioreceptor assays. The apparent pKa of the acid transition is 3.45 with an extremely slow and temperature-dependent rate at pH 2.0 (1.8 . 10(-4) s-1 at 37 degrees C). By gel filtration the molecular weight of the active hormone is estimated to be 45 ...
Guzeloglu A, Atli MO, Kurar E, Kayis SA, Handler J, Semacan A, Aslan S.The aims of the present study were to elucidate the expression profiles of leukotriene (LT) pathway mRNA transcription and to determine the possible interaction of LT and prostaglandin (PTG) pathways genes in equine endometrium during the estrous cycle and early pregnancy. Endometrial biopsies were obtained from mares on the day of ovulation (d0), at late diestrous (LD, n = 4), and after luteolysis in the estrus phase (AL, n = 4) of the cycle. Biopsies were also taken on Days 14 (P14; n = 4), 18 (P18, n = 4), and 22 (P22, n = 4) during early pregnancy that were comparable days to cyclic sampli...
Dunkel B, Rickards KJ, Werling D, Page CP, Cunningham FM.To determine whether expression of equine platelet activation-dependent surface markers is influenced by phospodiesterase (PDE) isoenzyme activity and whether antigen challenge alters platelet PDE activity in horses with recurrent airway obstruction (RAO). Methods: 16 horses. Methods: 7 healthy horses were used for in vitro experiments, 6 horses with RAO were used for antigen challenge, and 6 healthy horses were used as control animals. Three of the healthy horses had also been used in the in vitro experiments. Effects of PDE inhibition and activation of adenylyl cyclase on CD41/61 and CD62P e...
