Proteins are essential macromolecules that play diverse roles in the physiology and health of horses. They are composed of amino acids and are involved in various biological processes, including tissue growth, repair, and the synthesis of enzymes and hormones. Dietary proteins are a key component of equine nutrition, influencing muscle development, immune function, and overall performance. Horses require a balanced intake of essential amino acids, which must be obtained through their diet, as they cannot be synthesized endogenously. This page compiles peer-reviewed research studies and scholarly articles that explore the types, functions, and dietary requirements of proteins in horses, as well as their impact on equine health and performance.
Williams MA, Harrison PM.Horse ferritin was fractionated both by starch-gel electrophoresis and by gel filtration on Sephadex G-200. Monomer fractions contained up to 98% of monomer and oligomer fractions up to 76% of oligomers as determined by quantitative electron microscopy. Percentages obtained from electron micrographs correlated well with analytical starch-gel electrophoretograms and ultracentrifuge patterns. Amino acid analyses of monomer- and oligomer-enriched fractions showed no significant differences. Ferritin oligomers did not apparently dissociate on dilution for electron microscopy or on storage. Apoferr...
Turner GA, Taylor DM.The interactions between tetravalent plutonium and horse serum proteins were studied in vitro by electrophoresis on cellulose acetate and by gel filtration. The results show that in horse serum, as in other mammalian sera, the plutonium is associated principally with the transferrin component of the beta1-globulins. The formation of the plutonium-transferrin complex requires the presence of HCO3-, and plutonium is displaced from the complex by excess iron, thus indicating that similar binding sites may be involved in the complexing of iron and plutonium. The plutonium complex is considered to ...
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.
Oliver L, Hartree AS.The cystine-containing peptides of horse growth hormone were isolated and their amino acid sequences determined. Four unique half-cystine residues occur in two peptides, one containing 11 and the other, at the C-terminus of the protein, 15 amino acids. These sequences are compared with published data on growth hormones from other species.
O'Callaghan DJ, Hyde JM, Gentry GA, Randall CC.Infection of exponential-phase suspension cultures of mouse fibroblast cells (L-M) with equine abortion virus (EAV) resulted in inhibition of cell growth and marked alterations in host metabolic processes. The synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid was inhibited within 4 hr after infection and was suppressed by more than 90% by the time of maximal virus replication (14 to 18 hr). The overall rate of protein synthesis, however, was similar in uninfected and virus-producing cells as determined by measurements of net protein and isotope incorporation. The time course of vir...
Van Pelt RW.Physical, biochemical, and cytologic properties of synovial fluid from normal equine tarsal joints were investigated. Tarsal synovial fluid was pale yellow, clear, free of flocculent material, and did not clot. Volume varied in direct proportion to individual tarsal joint size. Relative viscosity was related to volume, polymerization and quantity of hyaluronic acid, and protein concentration. Mucinous precipitate quality (hyaluronic acid polymerization) was uniformly high. Results of certain analyses of serum were compared with those of tarsal synovial fluid. Tarsal synovial fluid protein conc...
Milne EM, Doxey DL, Gilmour JS.The analysis of peritoneal fluid is of value in the differential diagnosis of equine colic but its characteristics have not been evaluated in grass sickness. Peritoneal fluid was collected from 15 normal horses and from 11 cases of medical colic, 11 cases of surgical colic, 20 cases of acute grass sickness and 13 cases of subacute grass sickness. The fluid was analysed for its appearance, total and differential white cell count, specific gravity, total protein concentration and total and intestinal alkaline phosphatase activity. Fluid from cases of medical colic was normal in these respects. S...
Barbey C, Cauchard S, Cauchard J, Laugier C, Hartke A, Petry S.Rhodococcus equi remains a significant pathogen, causing severe pneumonia in foals. The development of vaccines and serologic diagnosis could be greatly facilitated by studying the humoral immune response to this equine pathogen. In this study, a crude extract of R. equi ATCC 33701-secreted proteins combined with the Montanide® ISA70 adjuvant was found to be highly immunogenic in mice with the highest titer of 99,000 on day 42 after the first subcutaneous immunization. This immune response was dependent on the quantity of proteins injected and the presence of adjuvant. By dot-blotting, eight ...
Ueno Y, Uemura R, Niwa H, Higuchi T, Sekiguchi S, Sasaki Y, Sueyoshi M.Equine proliferative enteropathy (EPE) caused by Lawsonia intracellularis is characterized by hypoproteinemia. There are currently no reliable reports that provide a reference value for the total serum protein (TP) concentration to clinically diagnose EPE. The objective of this study was to statistically determine the reference value. Feces and sera of 99 foals with EPE-like clinical signs and of 35 healthy foals were obtained. The samples were used for specific-gene detection of L. intracellularis, TP measurement, and specific-antibody detection against L. intracellularis. Based on these resu...
Dubin A, Potempa J, Turyna B.Horse blood leucocyte cytosol exhibits a broad inhibitory activity against serine proteinases. The purified inhibitor was exposed to investigated enzymes (trypsin, chymotrypsin, elastases and serine proteinase from S. aureus) for variable time and the products were analyzed by gradient polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The molar ratio I:E, association rate constants k on and inhibition constants Ki for the enzymes and inhibitor were determined. The examined elastases form stable, stoichiometric complexes with the inhibitor (Ki less than 10(-10) M), ...
Thway TM, Wolfe MW.Equids and primates are the only species known to express the placental hormone chorionic gonadotropin (CG). CG is a member of the heterodimeric glycoprotein family and is composed of an alpha subunit linked to a hormone-specific beta subunit. Previously, we have reported that epidermal growth factor (EGF) regulates the equine glycoprotein hormone alpha subunit promoter through a protein kinase C (PKC)/mitogen-activated protein kinase (MAPK) signal transduction pathway in trophoblasts. The current study investigates the regulatory element/factors involved in the induction of equine glycoprotei...
Liu ZQ, Xia J, Wang GL, Kuermanali N.Hyalomma asiaticum tick, an important ectozoic parasite causes tickle, pain, anemia, weight loss, and paralysis in its hosts, which include humans, cattle, sheep, horses, camels, and hares. The 4D8 gene can be a potential vaccine candidate antigen for H. asiaticum. In the present study, we cloned and expressed the 4D8 gene of H. asiaticum from Xinjiang Province. Primers were designed according to the H. asiaticum tick 4D8 gene sequence available in GenBank. The gene was amplified by reverse transcription-polymerase chain reaction and the fragments were subcloned into the prokaryotic expression...
Bewley TA, Li CH.The conformations of human, equine, and porcine pituitary prolactins, as evidenced by various optical properties, have been compared. The alpha-helix contents of all three proteins are essentially identical to each other (60 +/- 5%), as well as to prolactins isolated from other mammalian species. Direct absorption (zero and second-order), difference absorption, fluorescence emission, and circular dichroism spectra suggest that the majority of tyrosine and tryptophan side chains in these three proteins exist in very similar microenvironments within the folded forms of the hormones. Thus, the ge...
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...
Carpenter MA, Broad TE.Transferrin, the iron transport protein of the blood, is highly polymorphic in many species, including the horse. A number of sequence polymorphisms that distinguish several of the variants of horse transferrin are reported here. Previous studies indicated that exons 12 and 15 were likely to be polymorphic. Sequencing regions of exons 12 and 15 from D and R variants revealed 10 nucleotide substitutions that encoded six amino acid replacements. The F1, F2, H2, and * variants were identical to D, and the O variant was almost identical to R, in the regions studied. The data indicated that the hor...
Caffrey CR, Ryan MF.An excretory-secretory (ES) preparation derived from adult Strongylus vulgaris in vitro was assessed for proteolytic activity using azocasein and synthetic, fluorogenic, peptide substrates. Fractionation was by molecular sieve fast protein liquid chromatography (molecular sieve FPLC) and resolution by gelatin-substrate sodium dodecyl sulphate-polyacrylamide gel electrophoresis (gelatin-substrate SDS-PAGE). The cysteine proteinase activator, dithiothreitol (DTT), enhanced azocaseinolysis and hydrolysis of carbobenzoxy-phenylalanyl-arginine-7-amido-4-methylcoumarin (Z-Phe-Arg-NMec) by the ES pre...
Furr M, Chickering WR, Robertson J.To determine normal CSF electrophoresis patterns in horses, and to determine whether the electrophoretic scans from horses with cervical compression differ from those of neurologically normal horses. Methods: 32 horses assigned to 1 of 2 groups: neurologically normal (n = 18) or cervical compression (n = 14). Methods: CSF was collected from 18 neurologically normal horses referred to the Marion duPont Scott Equine Medical Center, and protein electrophoresis was performed to describe the normal equine CSF electrophoretogram. Results of CSF electrophoresis from 14 horses with cervical compressio...
Jalali GR, Rezai A, Underwood JL, Mowbray JF, Surridge SH, Allen WR, Matthias S.We have shown that most of the IgG present on term syncytiotrophoblast, membrane, microvesicles is bound to an 80 kDa protein antigen (R80K). Methods: Microvesicles were prepared from term human placenta, and the IgG eluted at pH3. Results: When IgG antibody was eluted at pH3 and reacted with acid-treated vesicles of other placentae, the alloantibody always bound to the preparation from which it was obtained, but only to about 10% of acid-treated preparations from other placentae. A similar polymorphic protein found in association with IgG antibody was found in term horse placentae. Cross-reac...
Böttiger LE.Erythrocyte sedimentation rate, total protein and fibrinogen, electrophoretic protein pattern, and total serum protein-bound carbohydrates have been determined in a number of domestic animals and compared to human values. The striking finding is that although the E.S.R. varies widely between various species, the fibrinogen content is of the same order of magnitude in all. The horse, which shows a very high E.S.R., has a well marked beta-globulin fraction as an outstanding feature, a finding that should be further studied. Blutsenkungsgeschwindigkeit, Gesamteiweiss und Fibrinogen, elektroforeti...
Atkinson JP.1. The globulins of both normal and diphtheria antitoxic serum exhibit chemically toward reagents the same reactions, being precipitated by magnesium sulphate and split up into fractions in precisely the same way. 2. All of the diphtheric antitoxic power of both normal and immunized serum is always carried by the globulin and its fractional precipitates. 3. During the fractional precipitation of the serum globulin of horses immunized from diphtheria toxin and horses not immunized from diphtheria toxin, some of the globulin is lost, likewise at the same time some of the antitoxic power of the g...
Braun J, Hochi S, Oguri N, Sato K, Torres-Boggino F.Three experiments were conducted to evaluate the effect of different macromolecule components (egg yolk, skim milk, and BSA) in a widely employed extender for cryopreservation of horse semen. Spermatozoal motility (MOT) and the percentage of spermatozoa with an intact plasma membrane (IPM) were evaluated in frozen-thawed samples. In the first experiment (four Draft Horse stallions, four ejaculates each) a standard freezing extender containing 20% whole egg yolk was modified by replacing extender components (glucose-EDTA solution, 11% lactose solution) with an increasing volume of a skim milk d...
Rousselle JC, Gillet G, Fillion G.The solubilization of the serotonergic 5HT1 and 5HT3 sites was performed with digitonin and sodium cholate at 1% (final concentration). Two binding sites for [3H]5HT were observed on rat or horse brain synaptosomal membranes solubilized with these detergents. The corresponding dissociation constants (KD) were 1-3 nM and 13-30 nM respectively. These values were closely similar to those corresponding to 5HT1 and 5HT3 sites located in intact membranes. The solubilized sites specifically bound 5HT. The effect of GTP decreasing the binding to 5HT1 sites was lost on solubilized 5HT1 sites; it was re...
Forsell PK, Lindberg A, Karlsson S, Lindgren JA, Claesson HE.It has been demonstrated that equine neutrophils, but not eosinophils, require exogenous arachidonic acid for calcium ionophore A23187-induced leukotriene synthesis. Because cytosolic phospholipase A(2) (cPLA(2)) plays an essential role in leukotriene formation in leukocytes, we investigated the presence of a functional cPLA(2) in equine neutrophils. To determine whether cPLA(2) from neutrophils was catalytically active, we purified the enzyme >6,500 fold with 3% recovery from equine neutrophils. The full-length cDNA sequence encoded a 749-amino acid protein. The deduced amino acid sequence...
Komori M, Higami A, Imai Y, Imaoka S, Funae Y.A form of P450 [termed P450(h-1)] was purified from the liver microsomes of a male horse to electrophoretic homogeneity. The specific content of the final P450(h-1) preparation was 14.8 nmol/mg of protein and the recovery was 0.38% of the microsomal P450. The apparent molecular weight of P450(h-1) was 52,000 Da. The absorption spectra of P450(h-1) indicated that P450(h-1) was a low- and high-spin mixed type P450 in the oxidized form. The reconstituted system containing P450(h-1) could catalyze benzphetamine N-demethylation, 7-ethoxycoumarin O-deethylation, and testosterone 16 alpha-hydroxylati...
Jimenez Rihuete P, Villarino N, Pelisiak A, Rubio-Martinez LM.Refractometric determination of total protein (TP) in synovial fluid (SF) is commonly used for diagnosis and monitoring of synovial sepsis in horses. Previous studies have shown that elevated concentrations of certain anticoagulants may overestimate refractometric determination of TP concentration. Objective: The aim of the study was to evaluate the effect of different concentrations of dipotassium EDTA (KEDTA) and lithium heparin (LH) on TP determination by using a hand-held refractometer in equine synovial fluid. Methods: Cross-section observational study. Methods: Thirty samples of synovial...
Butnev VY, Gotschall RR, Baker VL, Moore WT, Gout PW, Bousfield GR.Glycosylated equine prolactin (G-ePRL) and nonglycosylated ePRL were purified to homogeneity from side fractions obtained during isolation of LH/FSH from horse pituitaries. Both PRL forms were isolated together in high yield by the isolation procedure used for glycosylated porcine PRL/(G-pPRL) and pPRL, involving acetone extraction/precipitation, NaCl and isoelectric precipitation, and gel filtration. Purification of G-ePRL required additional Con A chromatography. The N-terminal amino acid sequencing for 32 cycles of G-ePRL and ePRL resulted in sequences identical to the known primary structu...
Leder L, Bosshard HR.It has long been known that antibodies to cytochrome c can distinguish between closely sequence-related cytochromes c. Because the 3-D-structure of the polypeptide chain is virtually identical among eukaryotic cytochromes c, antibody specificity is directed against amino acid substitutions within a common polypeptide folding pattern. The question arises if the specificity is observed at the level of the 3-D-structure (conformational epitopes) and/or at the level of the primary structure (sequential epitopes). Using rabbit sera to horse cytochrome c, we show that discrimination against the host...
Okabe T, Miyajima T, Nakagawa K, Tsukamoto S, Fujiwara K, Ikeguchi M.β-lactoglobulin forms a non-native α-helix during an early stage of folding. To address the role of the non-native structure in the folding process, we designed several mutants of equine β-lactoglobulin with reduced helical propensity in the non-native helix region. One of them, A123T, showed a similar structure to that of the wild-type protein; its folding kinetics was investigated by stopped-flow circular dichroism (CD) and fluorescence. Although A123T showed a reduced burst-phase CD intensity, its folding rate was similar to that of the wild-type protein, which indicated that the formati...
Salminen K.The levels of serum vitamin B were determined on 16 mature partly warm-blooded, partly Finnish rural-race horses by the radioisotopic competitive inhibition assay method. The mean value from three samplings carried out in dupli- or triplicate was 1.54 ± 0.16 ng/ml. The utilization of serum inorganic cobalt for cyanocobalamin synthesis was studied on two geldings, which received a dose of 200 µCi CoGl i.v. A Sephadex G-100 gel filtration was carried out with the serum proteins from serial blood samplings at different time intervals 15 min. to 48 hrs. after administration. The gel filtration s...
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...
Van Beek H, Baars AJ.Metallothioneins (MTs) were separated and quantitated by reversed-phase high-performance liquid chromatography (RP-HPLC), in direct combination with atomic absorption spectrometry (AAS) for quantitation of the metal contents in MTs. MTs were eluted from an RP-8 column with a gradient of Tris buffer pH 7.0 and methanol, and were detected by UV absorbance (220 nm). Commercially available purified MTs from horse kidney and rabbit liver were analyzed for purity and metal composition. One lot of horse kidney yielded only 50% of the estimated value. In some cases, the certified metal content differe...
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...
Alben JO, Bare GH.Infrared absorption spectra of the alpha-104 (G11) cysteine SH group have been observed for aqueous solutions of hemoglobin derivatives from humans, pigs, and horses. The center frequencies ((nu)SH) show ligand sensitive patterns that are similar for the three species, with (nu)SH (HbCO) <(nu)SH (HbO(2) ~ HbCN) < (nu)SH (Hb(+)) <<(nu)SH (deoxyHb) for human and pig hemoglobins. The alpha-104 SH group is most strongly H-bonded (smallest (nu)SH), has the greatest range of (nu)SH (Hb ? HbCO) in human hemoglobin, and is least strongly H-bonded and has the smallest range of (nu)SH (Hb ? HbCO) in hor...
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...
Rółkowski R, Worowski K, Skrzydlewski Z.Antiheparin activity of plasma of different species of vertebrates depends to a large extent on contents of low density lipoproteins (LDL). High antiheparin activity of the blood plasma of chicken and human corresponds to high contents of LDL and low antiheparin activity of the blood plasma of horse, cow, sheep, dog and pig corresponds to decreased contents of these proteins. Differences in the contents of fibrinogen, acid alfa1-glycoproteins, globulins, alkaline proteins and antithrombin III activity have smaller influence on antiheparin activity in the blood plasma of the examined animals.
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...
