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.
Babel I, Stella RC, Prado ES.Previous experiments indicated that horse urinary kallikrein (UK) hydrolyzes salminei- e and polyarginine, a but not polylysine. This paper reports the action of UK on bradykinyl-serine, methionyllysyl-bradykinin and lysyllysyl-bradykinin.
Holmes RS, Masters CJ.Multiple forms of soluble esterase activity have been resolved in horse, sheep, ox and possum tissue extracts and sera. 2. By comparing esterase zymograms from different tissues and from different species, it is apparent that the distribution and multiplicity of esterase activity is tissue and species specific. 3. By means of substrate and inhibitor studies, the esterase multiple forms have been characterized into four main classes : carboxylesterases, arylesterases, acetylesterases, and cholinesterases. Each of these can be considered as an isoenzymic group. 4. Evidence is presented for furth...
Rockey JH.Eight antigenically unique immunoglobulins have been identified in purified equine anti-p-azophenyl-beta-lactoside (Lac) antibody isolated from a single horse. The Fc fragments of the gammaGa-, gammaGb-, gammaGc-, and -gammaA-globulins have been shown to possess unique antigenic determinants. Common gammaG- and gammaA-Fc fragment antigenic determinants, which were absent from the 10Sgamma(1)- and gammaM-globulins, have also been observed. All antibody populations share two antigenically distinct light (B, L) chain variants. The association of anti-Lac antibody with the hapten p-(p-dimethylamin...
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...
Kundriutskova LA, Kruglikova RI.Hydrolysis of ethers of saturated and unsaturated alcohols and ethers, e.g. phenol and choline, under the action of horse blood serum cholinesterase, was studied. The reactivity towards enzymatic hydrolysis is decreased due to a greater length of the chain in the alcohol residue of the benzoic acid aminoethers; at nCH2 = 4 the compound is a poor substrate. An increase in nydrophobicity of the acyl residue of the ether molecule also leads to a decrease in the Vmax and Km values. In case of cholinesterase substrates, an increase in the molecule hydrophobicity results in an increase of its non-pr...
Roig M, Segura J, Ventura R.A method to quantify metabolites of 17beta-nandrolone (17betaN) in boar and horse urine has been optimized and validated. Metabolites excreted in free form were extracted at pH 9.5 with tert-butylmethylether. The aqueous phases were applied to Sep Pak C18 cartridges and conjugated steroids were eluted with methanol. After evaporation to dryness, either enzymatic hydrolysis with beta-glucuronidase from Escherichia coli or solvolysis with a mixture of ethylacetate:methanol:concentrated sulphuric acid were applied to the extract. Deconjugated steroids were then extracted at alkaline pH with tert-...
Meijer AE, van den Hoven R, Wensing T, Breukink HJ.Needle biopsies from m. gluteus medius of 22 horses which had suffered from repeated attacks of exertional myopathy were studied at various times after an attack, to determine if metabolic alterations can be demonstrated by enzyme histochemistry. Morphological changes and activity of 25 enzymes were studied. Immediately after onset of an attack, some large rounded fibres with a defect of the oxidative phosphorylation were seen. After some hours these fibres lost their glycolytic enzyme activity, followed by disappearance of mitochondrial enzyme activity with accumulation of Ca2+-containing sub...
Patan-Zugaj B, Egerbacher M, Licka TF.Angiogenesis and sepsis-related equine laminitis have several features in common. Both events can be induced by endotoxin (lipopolysaccharide- LPS) and both are associated with increased expression of the enzyme cyclooxygenase (COX), of which two isoforms (COX-1 and COX-2) exist. To examine the causal relationship between LPS exposure and COX expression and to investigate the tissue distribution of COX in the LPS-exposed tissue, the technique of extracorporeal haemoperfusion of isolated equine forelimbs was utilized. Perfusion was performed for 10Â hr under physiological conditions (control-pe...
Ascenzi P, di Masi A, Gullotta F, Mattu M, Ciaccio C, Coletta M.Cyanide binds to ferric heme-proteins with a very high affinity, reflecting the very low dissociation rate constant (k(off)). Since no techniques are available to estimate k(off), we report herewith a method to determine k(off) based on the irreversible reductive nitrosylation reaction to trap ferric myoglobin (Mb(III)). The k(off) value for cyanide dissociation from ferric cyanide horse heart myoglobin (Mb(III)-cyanide) was determined at pH 9.2 and 20.0 degrees C. Mixing Mb(III)-cyanide and NO solutions brings about absorption spectral changes reflecting the disappearance of Mb(III)-cyanide w...
Snijder EJ, Wassenaar AL, Spaan WJ.To study the proteolytic processing of the equine arteritis virus (EAV) replicase open reading frame 1a (ORF1a) protein, specific antisera were raised in rabbits, with six synthetic peptides and a bacterial fusion protein as antigens. The processing of the EAV ORF1a product in infected cells was analyzed with Western blot (immunoblot) and immunoprecipitation techniques. Additional information was obtained from transient expression of ORF1a cDNA constructs. The 187-kDa ORF1a protein was found to be subject to at least five proteolytic cleavages. The processing scheme, which covers the entire OR...
Brimijoin S, Mintz KP, Prendergast FG.Interactions between dansylarginine N-(3-ethyl-1,5-pentanediyl)amide (DAPA) and the cholinesterases were examined by the techniques of enzyme kinetics and fluorescence spectroscopy. When tested with partially purified enzyme preparations, DAPA was a potent inhibitor of butyrylcholinesterase (IC50 = 2 x 10(-7) M) but not of acetylcholinesterase (IC50 = 4 x 10(-4) M). For a detailed study of the effects of DAPA on butyrylcholinesterase (BuChE), the enzyme was purified to homogeneity from horse serum, with the aid of affinity chromatography on N-methyl acridinium. The kinetics of the inhibition o...
de Val N, Herschbach H, Potier N, Dorsselaer AV, Crichton RR.An essential difference between eukaryotic ferritins and bacterioferritins is that the latter contain naturally, in vivo haem as Fe-protoporphyrin IX. This haem is located in a hydrophobic pocket along the 2-fold symmetry axes and is liganded by two Met 52. However, in in vivo studies, a cofactor has been isolated in horse spleen apoferritin similar to protoporphyrin IX; in in vitro experiments, it has been shown that horse spleen apoferritin is able to interact with haem. Studies of haemin (Fe(III)-PPIX) incorporation into horse spleen apoferritin have been carried out, which show that the me...
Coyne CP, Smith JE, Keeton K.A selected group of pharmaceutical compounds were evaluated for the ability to inhibit the biochemical activity of fibrinoligase (coagulation factor XIIIa*) in pooled equine plasma. Criteria for the pharmaceuticals selected were based on the mechanism of the transglutamination biochemical reaction mediated by coagulation factor XIIa*. These criteria were complemented by recognition of the molecular configuration and chemical composition of amino acid residue side chains involved in the process of covalent fibrin monomer polymerization (cross-linking, transglutamination) mediated by this enzyme...
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...
Xu J, Cai J, Suresh M, Peek SF, Darien BJ.Equine PSGL-1 (ePSGL-1) is widely expressed on equine PBMC as a homodimer with sialylation (sLeX) modifications that contribute to P-selectin binding affinity. To investigate the role of other potential post-translational modifications required for high-affinity P-selectin binding, ePSGL-1 was transfected into CHO cells expressing equine FucT-VII and/or C2GnT. P-selectin-IgG chimera binding by ePSGL-1 transfected into CHO cells only occurred when both FucT-VII and C2GnT were expressed, establishing that fucosylation and core-2 branching are required as post-translational modifications for high...
Tung JT, Venta PJ, Eberhart SW, Yuzbasiyan-Gurkan V, Alexander L, Caron JP.To determine the effects of recombinant equine interleukin -1beta (reIL-1beta) and 4 anti-inflammatory compounds on the expression and activity of cyclooxygenase (COX)-2 in cultured equine chondrocytes. Methods: Articular cartilage from 9 young adult horses. Methods: Reverse transcriptase-polymerase chain reaction methods were used to amplify a portion of equine COX-2 to prepare a cDNA probe. Northern blot analysis was used to quantify the expression of COX-2 in first-passage cultures of equine articular chondrocytes propagated in media containing dexamethasone (DEX), phenylbutazone (PBZ), pol...
Perelygin AA, Lear TL, Zharkikh AA, Brinton MA.Mammalian 2'-5' oligoadenylate (2-5A) synthetases are important mediators of the antiviral activity of interferons. Both human and mouse 2-5A synthetase gene families encode four forms of enzymes: small, medium, large and ubiquitin-like. In this study, the structures of four equine OAS genes were determined using DNA sequences derived from fifteen cDNA and four BAC clones. Composition of the equine OAS gene family is more similar to that of the human OAS family than the mouse Oas family. Two OAS-containing bovine BAC clones were identified in GenBank. Both equine and bovine BAC clones were phy...
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...
Westermann CM, de Sain-van der Velden MG, van der Kolk JH, Berger R, Wijnberg ID, Koeman JP, Wanders RJ, Lenstra JA, Testerink N, Vaandrager AB....Two horses (a 7-year-old Groninger warmblood gelding and a six-month-old Trakehner mare) with pathologically confirmed rhabdomyolysis were diagnosed as suffering from multiple acyl-CoA dehydrogenase deficiency (MADD). This disorder has not been recognised in animals before. Clinical signs of both horses were a stiff, insecure gait, myoglobinuria, and finally recumbency. Urine, plasma, and muscle tissues were investigated. Analysis of plasma showed hyperglycemia, lactic acidemia, increased activity of muscle enzymes (ASAT, LDH, CK), and impaired kidney function (increased urea and creatinine). ...
Kettler MK, Weil MR, Mascotti K, Perryman LE.A group of diseases termed combined immunodeficiency (CID) results in a severe form of immunodeficiency. While CID in humans has two genetics bases, in Arabian it is inherited in an autosomal recessive manner. Kettler et al. (1989) determined that uric acid was significantly (p 0.05) between carrier and non-carrier horse's serum levels of hypoxanthine or xanthine. These data, combined with our previous ones suggest that an enzymatic lesion in the purine salvage pathway may occur at the urate oxidase step. ZUSAMMENFASSUNG: Serum-Hypoxanthin- und -Xanthin-Spiegel in Pferden mit Heterozygotie fÃ...
Björkman C.1. Comparative data are presented of the activities of pyruvate dehydrogenase complex and acetyl-CoA synthetase and of the acetate content in homogenates from ventral grey matter in spinal cord from cows and two non-ruminant species, pigs and horses. The methods used in the study are evaluated and discussed. 2. The total pyruvate dehydrogenase complex activity was 24.9-29.9 mU/mg protein and did not differ between the species. The part of the complex that was in active form at the sampling occasion was 60, 85 and 95% in cows, pigs and horses, respectively. 3. Acetyl-CoA synthetase activity dif...
Daraban Bocaneti F, Altamura G, Corteggio A, Tanase OI, Dascalu MA, Pasca SA, Hritcu O, Mares M, Borzacchiello G.Bovine papillomaviruses -1/-2 (BPVs) are small non-enveloped double-stranded DNA viruses able to infect the skin of bovids and equids, causing development of neoplastic lesions such as bovine cutaneous fibropapillomas and equine sarcoid. Matrix metalloproteinases (MMPs) are a group of zinc-dependent endopeptidases that degrade basal membrane and extracellular matrix, whose function is essential in physiological processes such as tissue remodeling and wound healing. MMPs activity is finely regulated by a balancing with expression of tissue inhibitors of MMPs (TIMPs), a process that is impaired ...
Ledwozyw A, Kadziołka A, Jabłonka S, Tusińska E, Herbut M.The aim of this study was to investigate the platelet factor 3 activity in platelet-rich plasma of horse, cattle, sheep and pig, by the use of chromogenic tripeptide substrate H-D-Phenylalanyl-Pipecolyl-Arginyl-p-nitroanilide. Among species examined the highest activity of this factor was stated in pig, the lowest one in sheep. Chromogenic substrate test was 10 times more sensitive that Stypven clotting time test. Thus, the use of chromogenic tripeptide substrate is fully valuable in platelet factor 3 activity estimation in domestic animals.
Theodorakis JL, Armes LG, Margoliash E.beta-Thiopropionyl derivatives of horse cytochrome c singly modified at each of 18 different lysine epsilon-amino groups have been prepared using sulfosuccinimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate and purified to homogeneity by high-pressure liquid chromatography. These derivatives were characterized by determination of: (i) the location of the modification; (ii) reduction potentials; (iii) visible and NMR spectra: and by (iv) measurement of electron transfer activity with cytochrome-c oxidase. No significant changes in structure were indicated, except for the ferric forms of the deri...
van Aken D, Zevenhoven-Dobbe J, Gorbalenya AE, Snijder EJ.The positive-stranded RNA genome of the arterivirus Equine arteritis virus (order Nidovirales) encodes the partially overlapping replicase polyproteins pp1a (1727 aa) and pp1ab (3175 aa). Previously, three viral proteinases were reported to cleave these large polyproteins into 12 non-structural proteins (nsps). The chymotrypsin-like viral main proteinase residing in nsp4 is responsible for eight of these cleavages. Processing of the C-terminal half of pp1a (the nsp3-8 region) was postulated to occur following either of two alternative proteolytic pathways (the 'major' and 'minor' pathways). He...
Kasza A, Korpula-Mastalerz R, Rose-John S, Dubin A.The horse leucocyte elastase inhibitor (HLEI), present in neutrophils, monocytes and bone marrow cells, is apparently a cytoplasmic protein which is not released from cells even in response to stimulation with lipopolysaccharide, phorbol ester, tumour necrosis factor alpha, interleukin-1 or elastin degradation products. Although no expression of the inhibitor was detected in neutrophils, both monocytes and bone marrow cells were efficient in its synthesis. Using a new expression vector pREST5d, recombinant inhibitor was produced in a large quantity in a soluble form, with a yield of 88 mg per ...
Franken P, Schotman JH.The activities and concentrations of a number of erythrocytic enzymes and intermediate products of erythrocyte metabolism were determined in twenty-one normal standard-bred horses which were studied clinically and biochemically. These studies showed that equine anaerobic glycolysis is characterized by a biochemical pattern similar to that observed in human PK deficiency. The greater sensitivity of equine haemoglobin to oxidants is attributable either to low stability of GSH, which may be due either to the low activity of GR or that of 6PGD as observed in the studies. In addition, the saturatio...
Le Goff D, Hannan J, Maboundou JC, Ayrault-Jarrier M.Equine plasma lipoproteins were fractionated into VLDL, LDL-1, LDL-2 and HDL by density gradient ultracentrifugation. From each lipoprotein fraction, five apo C like peptides of approx. M(r) 1400, 10000, 9500, 9000 and 8000 were detected by SDS-polyacrylamide gel electrophoresis. After partial purification by Sephadex G-75, one fraction, showing a strong activation of lipoprotein lipase, was further purified by Mono Q anion exchange column. Two of the apo C like peptides (M(r) 10000 and 8000) activated the bovine milk lipoprotein lipase in vitro; only one (M(r) 9500) inhibited the lipolytic ac...
Leblová S, Galociová J, Cerovská N.The studied herbicides (terbutylazine, simazine) inhibit the activity of plant, animal, and yeast alcohol dehydrogenases. The inhibition constant Ki for alcohol dehydrogenase (ADH) isolated from peas and bakers' yeast equals approximately 10(-4) M, and that for ADH isolated from horse liver is of the order of 10(-5) M. The character of inhibition for all the herbicides studied for the reaction catalyzed by pea, liver, and yeast ADH is always noncompetitive toward ethanol and competitive with respect to NAD. The inhibition constants for the enzyme isolated from peas are pH independent. The inte...
Raulo SM, Maisi P.To determine whether gelatinolytic activity in tracheal epithelial lining fluid (TELF), blood neutrophils, and blood lymphocytes from horses was metalloprotease activity, and to compare, for healthy horses and horses with chronic obstructive pulmonary disease, gelatinolytic activity in neutrophils, lymphocytes, and serum with activity in TELF. Methods: 7 horses with chronic obstructive pulmonary disease (COPD) and 4 healthy control horses. Methods: Neutrophils and lymphocytes were obtained by means of Percoll separation. Zymography was used to detect gelatinolytic activity; EDTA inhibition and...
Cross AR, Higson FK, Jones OT, Harper AM, Segal AW.1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrom...
Nazmutdinov RR, Bronshtein MD, Zinkicheva TT, Hansen NS, Zhang J, Ulstrup J.Outer-sphere electron transfer (ET) between optically active transition-metal complexes and either other transition-metal complexes or metalloproteins is a prototype reaction for kinetic chirality. Chirality as the ratio between bimolecular rate constants of two enantiomers mostly amounts to 1.05-1.2 with either the Λ or Δ form the more reactive, but the origin of chirality in ET parameters such as work terms, electronic transmission coefficient, and nuclear reorganization free energy has not been addressed. We report a study of ET between the Λ-/Δ-[Co(Ox)3](3-) pair (Ox = oxalate) and hor...
