Topic:Protein
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.
Activation of pigeon erythrocyte adenylate cyclase by cholera toxin. Partial purification of an essential macromolecular factor from horse erythrocyte cytosol. A cytosolic, macromolecular factor required for the cholera toxin-dependent activation of pigeon erythrocyte adenylate cyclase and cholera toxin-dependent ADP-ribosylation of a membrane-bound 43,000 dalton polypeptide has been purified 1100-fold from horse erythrocyte cytosol using organic solvent precipitation and heat treatment. This factor, 13,000 daltons, does not absorb to anionic or cationic exchange resins, is sensitive to trypsin or 10% trichloroacetic acid and is not extractable by diethyl ether. Activation of adenylate cyclase by cholera toxin requires the simultaneous presence of AT...
Rapid-scanning spectral evidence for catalytically nonequivalent but interconvertible forms of equine liver alcohol dehydrogenase. These rapid-scanning stopped-flow kinetic studies of the equine liver alcohol dehydrogenase-catalyzed reduction of p-nitrobenzaldehyde by NADH and (4R)-4-deuterio NADH (NADD) under single turnover conditions establish : (1) The reaction is biphasic using NADD as coenzyme, k1 approximately 200 sec-1, k2 = 0.5 sec-1 and the amplitude ratio (A1)/(A1 + A2) approximately equal to 0.5. (2) Each phase of the reaction involves the oxidation of enzyme-bound reduced coenzyme. (3) The recycling of sites in the presence of 20 mM pyrazole is negligible. (4) The rates of E(NAD-pyrazole) complex formation at...
Fibrinolytic activity without fibrinogenolysis during long-distance racing in horses. 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...
Predicted secondary structure of horse muscle acylphosphatase. Comparison with circular dichroism measurements. We have predicted the secondary structure of horse muscle acylphosphatase by the statistical method of Chou and Fasman. In addition, we have studied the circular dichroism spectra of the enzyme, obtaining values for comparison to the predicted results. Discrepancies were found for the alpha-helix content estimated by the two methods.
[Circadian variations in the content of plasma constituants in the brood mare]. Twenty-one circadian blood sample profiles were made in heavy brood mares during pregnancy, lactation or the dry, non-pregnant period. The mares were fed forage-rich diets containing different levels of energy and nitrogen (table 1). Each profile consisted of 7 samples taken at 8 a.m., 11 a.m., 3 p.m., 7 p.m., 11 p.m., 4 a.m. and 8 a.m. The animals were fed at 8:30 a.m. The eleven plasma components evaluated were glucose, non-esterified fatty acids, beta-hydroxybutyrate, acetate, alanine, insulin (energy metabolites), urea, total protein (nitrogen metabolites), calcium, inorganic phosphorus an...
Variations in the properties of equine chorionic gonadotropin. The objectives of this paper are to review the chemical and biological properties of equine chorionic gonadotropin (eCG, PMSG) isolated from the serum. Comparisons are made with eCG isolated from endometrial cups, trophoblast cell culture medium, and low titer serum. The results show that eCG can vary, depending on the source, in both chemical and biological (LH and FSH activity) properties.
Interaction of horse plasma antithrombin III and alpha 1-proteinase inhibitor with some serine proteinases. Antithrombin III and alpha 1-proteinase inhibitor isolated simultaneously from horse citrated plasma were tested for inhibitory activity against bovine trypsin and chymotrypsin, as well as elastase-like neutral proteinases from horse leucocytes. The stoichiometry of reaction and kinetic parameters (kass, Ko) were estimated and related to the protein pattern obtained after exposure of these proteinases to horse inhibitors as analyzed by polyacrylamide gel electrophoresis (PAGE and PAGE-SDS). As shown by fast reaction rates and low values of dissociation constants the two inhibitors effectively ...
[Variations in plasma components in lactating mares at late pregnancy-early lactation (author’s transl)]. In an experiment comparing pregnant then lactating mares with dry non-pregnant mares, the changes in plasma components were studied as indicators of the metabolic utilization of energy (glucose, non-esterified fatty acids, beta-hydroxybutyrate), nitrogen (urea, proteins) or minerals (calcium, phosphorus, magnesium). The mares were fed daily 2 kg concentrate and hay ad libitum. Beta-hydroxybutyrate, magnesium and to a lesser extent glucose were the only constituents whose levels were affected within the period starting one month before and ending one month after foaling. The increase in food in...
Antigen-antibody crossed electrophoretic studies and quantitative comparisons of serum transferrin types in horses. Selected transferrin phenotypes from 14 horses were investigated by antigen-antibody crossed electrophoresis. Horse sera were subjected to starch gel electrophoresis followed by right angle electrophoresis in agarose gels containing rabbit produced anti-horse transferrin. This technique gave an additional zone in the front as compared with 2 transferrin zones seen after ordinary starch gel electrophoresis. Comparisons of transferrin concentrations in horse sera were performed by an immunodiffusion technique. Values were related to a chosen reference serum. A total of 372 horses (210 Norwegian ...
Characterization of the binding of Triton X-100 to equine and rabbit serum albumin. The binding isotherms for Triton X-100 binding to equine and rabbit serum albumin were determined by equilibrium dialysis at 16 degrees C in pH 7.0, I = 0.05 phosphate buffer. Presented in a Scatchard plot, the binding isotherms are a straight line, indicating thermodynamically independent and identical binding sites. In this model equine serum albumin is characterized as having 11 such sites with an equilibrium constant of 6.0 x 10(3) M-1. Similarly, rabbit serum albumin is characterized as having 9 such sites with an equilibrium constant of 8.0 x 10(3) M-1.
In vitro host range of equine infectious anemia virus. Equine infectious anemia virus (EIAV) was successfully inoculated onto cell cultures of canine and feline origin, resulting in chronic infections in these cultures. Infection of equine cell cultures, which were the previous sole in vitro source demonstrated for virus production, was also performed for comparative purposes. Determination of the nature of the virus produced in the heterologous as well as the equine cells was accomplished in several ways. SDS-PAGE of purified virus from the different cell lines indicated very similar protein composition. Immunological identity was observed in gel...
Fractionation and partial characterization of alpha-1-protease isoinhibitors of horse. The principal alpha-1-protease inhibitor of horse was fractionated by classical methods and analysed with a modified fibrinogen-agarose gel electrophoretic method of high sensitivity and resolving power. Starting with an electrophoretically homogeneous inhibitor in unfractionated serum, two isoinhibitor bands became apparent after fractionation with (NH4)2SO4 and DEAE-cellulose DE-52 ion-exchange chromatography. The isoinhibitors differed in electrophoretic migration and in the elution pattern from Sephadex G-100 gel filtration, but possessed identical antigenic determinants and enzyme specifi...
Helix packing and subunit conformation in horse spleen apoferritin. An electron density map of horse spleen apoferritin at 0.28-nm (2.8 A) resolution and its preliminary interpretation have been described previously. Rigorous examination of this and newer maps at the same nominal resolution but calculated from more extensive data sets, including model building in a Richards' comparator, now allows us to report on structural features in more detail. We list inter-helical angles within and between neighbouring subunits, and describe a new short region of inter-subunit anti-parallel pleated sheet. A short section of electron density not properly accounted for in ...
[The immunological relation between human and equine Gc proteins (author’s transl)]. The immunological comparison of human and equine Gc proteins showed partial identical reactions between both species. Immunizations of goats and rabbits with horse serum produced antisera able to recognize human Gc proteins.
Sequence of the low activity equine erythrocyte carbonic anhydrase and delineation of the amino acid substitutions in various polymorphic forms. the sequence of the low activity form of equine erythrocyte carbonic anhydrase has been determined. The most common electrophoretic form, designated D, has been found to have five substitutions. Amino acid exchanges in the electrophoretic variants known as A1, A2, B, and T have been found at six other positions. The data do not permit calculation of the number of polymorphic forms of this enzyme. The equine D isozyme and the analogous human enzyme are quite homologous, 211 of their 260 residues, or 81%, being identical.
The disposition of calcium within parathyroid tissue. The disposition of 45Ca was studied in equine parathyroid gland slices. This preparation was shown to be viable by its ability to carry out protein synthesis, by the responsiveness of its respiration to effectors of oxidative phosphorylation, and by its calcium-inhibitable PTH secretion. 45Ca accumulates in the slices as the extracellular calcium is raised through the range in which physiological serum calcium concentration lies. The tissue slices behave as if they have no calcium pump: (a) depriving the cells of energy by treatment with antimycin A does not admit more calcium to the tissue, (...
The complete amino acid sequence of horse muscle acylphosphatase. The amino acid sequence of horse muscle acylphosphatase is given in the present paper. The carboxymethylated enzyme consists of a single polypeptide chain of 98 amino acid residues with an acetyl group blocking the NH2 terminus and a tyrosine at the COOH terminus. The calculated molecular weight of the native protein, a mixed disulfide with glutathione, is 11,365. The carboxymethylated protein was cleaved by cyanogen bromide. The three expected fragments were purified; moreover, an additional fragment, derived from a partial failure of cleavage at methionine-24, was purified and characterized....
Assembly of intra- and interspecies hybrid apoferritins. An intraspecies hybrid apoferritin was assembled by mixing subunits of horse heart ferritin, which consists mainly of H-type subunits, and horse spleen ferritin, in which L-type subunits predominate. Interspecies hybrid apoferritins were reconstituted from subunits of human liver-horse spleen ferritins and from rat liver-horse spleen ferritins. All the hybrid ferritins migrated as single zones with electrophoretic mobilities intermediate between those of the parent ferritins. Isoelectric focusing data and immunological patterns were consistent with the view that the reassembled apoferritins we...
[Hemoglobins, XXXIII. Note on the Sequence of the hemoglobins of the horse (author’s transl)]. The sequence analysis of the slow migrating component of the hemoglobins of horse was repeated with the automatic methode in the sequenator and the sequence of the beta-chains completed. In the alpha-chains the positions of alpha63 and alpha65 (Gly, Ala) and alpha82 and alpha85 (amides) were changed and the remaining 40 sequences of the beta-chains are reported. According to these data and biological contributions of other authors, the biological aspects of the primary structure and the polymorphism of the hemoglobins of the horse are discussed.
Enzyme-linked immunosorbent assay, using staphylococcal protein A for detecting virus antibodies. A modification of the indirect enzyme-linked immunosorbent assay (ELISA) was developed which used staphylococcal protein A linked to horseradish peroxidase. Virus antibodies in equine, bovine, porcine, feline, canine, lagomorphic (rabbit), and human sera were detected, using the indirect ELISA in which the antiglobulin enzyme conjugate was replaced by protein A linked to horseradish peroxidase. Results of the ELISA were compared with the results of the serum-virus neutralization test. The application of the test in laboratories performing serologic assays with sera from diverse animal species ...
The effect of trypsin digestion on the structure and iron-donating properties of transferrins from several species. The effect of trypsin digestion on iron-saturated and iron-free (apo) human, rabbit, bovine, pig and horse tranferrins has been studied. Iron-binding fragments were produced only from iron-saturated pig and bovine transferrins although some cleavage of the polypeptide chain occurred in all cases. The apo-transferrins were generally degraded to a greater extent than the corresponding iron-saturated proteins. The ability of the different transferrins to donate iron to rabbit reticulocytes varied in the order rabbit approximately pig greater than human approximately horse greater than bovine. Try...
Involvement of lysines-72 and -79 in the alkaline isomerization of horse heart ferricytochrome c. Spectrophotometric titrations of five singly modified horse heart ferricytochromes c, specifically (trifluoromethyl)phenylcarbamylated (CF3PhNHCO-) or trifluoroacetylated (CF3CO-) at lysines-13, -72, and -79, were carried out. The CF3PhNHCO-Lys-13, Lys-79, and CF3CO-Lys-79 derivatives all underwent alkaline isomerization with loss of the 695-nm band to low-spin species with an apparent pK of about 8.9, as did the unmodified cytochrome. However, modification of lysine-72 appeared to alter the reaction pathway since the CF3PhNHCO-Lys-72 derivative isomerized to a high-spin form with an apparent ...
Purification by affinity chromatography and characterization of a neutral alpha-glucosidase from horse kidney. A horse kidney neutral alpha-D-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) was purified about 580-fold with a yield of 33% by an affinity chromatography technique using the p-aminophenyl-beta-D-maltoside, a substrate derivative, as ligand. The purified enzyme, homogeneous in polyacrylamide gel electrophoresis, was a glycoprotein with a molecular weight of 280 000 as calculated by gel filtration and its isoelectric focusing points was found to be pH 4.1. The purified enzyme was able to hydrolyze various substrates having (alpha-1,2), (alpha-1,3), (alpha-1,4), and (alpha-1,6) glu...