Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Tissue distribution and blood levels of gamma-glutamyl transferase in the horse. In the horse, gamma-glutamyl transferase (GGT) was found to be mainly located in the kidneys, liver and pancreas. As renal lesions are followed by a urinary escape of enzyme, it can be assumed that if there are raised serum enzyme levels then the source will be chiefly from the liver and pancreas. In the blood, GGT can be measured either in plasma or serum. Its mean level in 58 horses was 12 U/L. This level was not affected by moderate dilution or slight haemolysis and its activity was only slightly decreased by storage at--30 degrees C. The relative hepatic specificity of this enzyme and its ...
Studies on the synovia in healthy horses with particular reference to the protein composition. Synovial fluid and blood were collected from 18 clinically healthy brood mares in resting conidition. The following parameters were analysed: total leucocytes, glucose, alkaline phosphatase (AP), lactate dehydrogenase (LDH), total protein, albumin, total globulin, albumin/globulin ratio and electrophoretic protein picture. The serum/synovia ratios were calculated for all parameters. It was considered to be of greater diagnostic value to compare these serum/synovia ratios rather than to look at the individual concentrations in synovia. The results obtained did not materially differ from those i...
Some haematological and biochemical parameters in race horses in Hong Kong. Haematological and biochemical values were determined in 2 groups of flat-race horses, which were trained on the same track in Hong Kong. The first group comprised 217 horses (435 blood samples) from various training strings. The second group, 66 horses (309 blood samples) were from one string kept under similar managemental conditions, but given salts by stomach tube 8 hours before blood sampling. Both groups were sub-divided to show the efs, thus confirming work by other authors. The lower haematological values in the group of horses given salts were discussed and the effect of water retenti...
The activity of purine salvage pathway enzymes in murine and horse models of congenital and acquired dysimmunity. Previous studies of human congenital immunodeficiency states and in vitro observations of lymphocyte response to mitogens have implicated two purine salvage pathway enzymes, andenosine deaminase (ADA) and nucleoside phosphorylase (NP), as critical in the normal maturation and/or function of the immune system. Based on this information, ADA and NP activities were examined in a variety of congenital and acquired animal models of dysimmunity. The animals studied herein included: congenitally athymic (nude) mice; congenitally asplenic mice; congenitally athymic-asplenic mice; motheaten mice; New Z...
Isolation and properties of prophospholipase A2 and phospholipase A2 from horse pancreas and horse pancreatic juice. Two phospholipases A2 (EC 3.1.1.4) with different isoelectric points have been isolated from horse pancreas in high yield (880 mg/kg tissue). From pancreatic juice the more acidic species was isolated as the sole phospholipase A2. Upon tryptic activation the zymogens release a hepta- and pentapeptide, respectively from the N-terminal part of the protein giving rise to the formation of one single enzyme with a specific activity higher than that of pancreatic phospholipases A2 from other mammalian species. Horse phospholipase A2 differs from the porcine and bovine enzymes with respect to amino a...
Chromatographic determination of some corticosteroids, with special reference to horse doping. Some chromatographic procedures, which can be used to detect and determine certain corticosteroids in samples from race horses, are described. These procedures include thin-layer, gas and high pressure liquid chromatography.
IgM antibody–I. Heterogeneity of the component chains of equine anti-lactose antibody. The heterogeneity of the IgM response has been studied with anti-lactose antibody purified from the sera of seven horses. The IgM antibody was induced with a bacterial vaccine and the sera were obtained during a one-year period of immunization. L and H chain preparations were derived from separate bleedings of each horse and examined by analytical isoelectric focusing. All of the L chain preparations were complex and similar and, under optimum conditions, exhibited about 45 bands. Their similarity included almost identical concentration distributions over the entire pH gradient. Isoelectric ba...
Prostaglandin F2alpha specific binding in equine corpora lutea. Preliminary studies indicate the presence of PGF2alpha specific binding sites in membrane fractions prepared from equine corpora lutea. The equilibrium binding data indicate an apparent dissociation constant of 3.2 X 10(-9)M and the concentration of binding sites of -0.1 pmoles/mg membrane protein. Competition of several natural prostaglandins for equine luteal PGF2alpha specific binding sites indicates specificity for the 9alpha-hydroxyl moiety and the 5,6-cis doublebond. Significant increases in relative binding affinities were demonstrated for PGF2alpha analogs with a phenyl ring introduced...
Amino acid sequence of phospholipase A2 from horse pancreas. The complete amino acid sequence of phosphlipase A2 (EC 3.1.1.4) from horse pancreas was determined. The protein controls of a single polypeptide chain of 125 amino acids and has a molecular weight of 13,927. The chain is crosslinked by seven disulfide bridges. The sequence was determined by automated Edman degradation of the intact protein and several of the large peptide fragments. Smaller peptides were analyzed by manual Edman degradation. Fragmentation of the peptide chain was accomplished by enzymatic digestion with trypsin, chymotrypsin, and thermolysin. The final overlap was found by di...
Steady state kinetics and binding of eukaryotic cytochromes c with yeast cytochrome c peroxidase. 1. The steady state kinetics for the oxidation of ferrocytochrome c by yeast cytochrome c peroxidase are biphasic under most conditions. The same biphasic kinetics were observed for yeast iso-1, yeast iso-2, horse, tuna, and cicada cytochromes c. On changing ionic strength, buffer anions, and pH, the apparent Km values for the initial phase (Km1) varied relatively little while the corresponding apparent maximal velocities varied over a much larger range. 2. The highest apparent Vmax1 for horse cytochrome c is attained at relatively low pH (congruent to 6.0) and low ionic strength (congruent to...
Transmission of the cytochrome c structural gene in horse-donkey crosses. Donkey cytochrome c was shown to differ from horse cytochrome c by having a serine in position 47 rather than a threonine. The rest of the amino acid sequences are identical. Mules and hinnies, both males and females, carry equal amounts of horse and donkey cytochromes c. The same ratio is found in hinnies in preparations from heart tissue and from skeletal muscle. These results demonstrate that cytochrome c is transmitted in horse-donkey crosses as a simple Mendelian character which is neither sex-linked nor shows dominance. The cytochrome c gene is therefore located in the nuclear genome, as...
Guanidination of horse methemoglobin. Reaction of horse methemoglobin with O-methylisourea at pH 10.2 results in 95% conversion of lysine residues to homoarginine. Analysis of the chymotryptic peptides showed that no single ϵ-amino group was unreactive. Guanidination decreases the dependence of the sedimentation coefficient on hydrogen ion concentration in the range of pH 8 to 11 and did not affect the dependence on protein concentration at pH 7. These results support the conclusion that the lysine side chains involved in subunit contacts have sufficient freedom to accommodate the small changes in bulk and geometry associated wit...
Determination of total and ultrafilterable calcium and magnesium in normal equine serum. Total and ultrafilterable calcium (Ca) and magnesium (Mg) values were determined for Shetland pony stallions, stallions, and pregnant and diestrous mares, using a simple, inexpensive, quick procedure to obtain an ultrafiltrate of serum. There was no significant difference between horses and ponies, between stallions and mares, or between pregnant and nonpregnant mares. The percentage of total serum Ca that was ultrafilterable was 63.4+/-1.7 for horses and 64.8+/-2.2 for ponies. The percentage of total serum Mg that was ultrafilterable was 75.6+/-1.5 for horses and 77.0+/-1.7 for ponies. Total ...
Amino acid composition of casein isolated from the milks of different species. Casein was isolated from the milks of the following species: cow, horse, pig, reindeer, caribou, moose, harp seal, musk-ox, polar bear, dall sheep, and fin whale. The caseins were subjected to acid hydrolysis, the resultant amino acids were converted to their n-butyl-N-trifluoroacetyl esters, and the amino acid composition of the caseins was determined by gas chromatographic analysis of these esters. Notable among the results was the close similarity, with respect to amino acid composition, of reindeer and caribou caseins. The results of the amino acid analyses of the other caseins are present...
Reaction of bovine and equine growth hormones with tetranitromethane. Bovine and equine growth hormones were chemically modified with tetranitromethane, at pH 7.4 during 5 h and at pH 8.0 in the presence of 8 M urea during 1 h. a) Both hormones have very similar but not identical reactivities. b) The nitration of the reactive tyrosines and tryptophan residues at pH 7.4 produces no detectable changes in their immunological or somatotrophic activities. C) The nitration of all tyrosine residues in both hormones gives rise to a complete loss of somatographic activity with no alteration of the immunological activity.
Purification and characterization of equine herpesvirus-induced DNA. Infection of cells with equine herpesvirus type 1 (EHV-1) or type 3 (EHV-3) resulted in the induction of a DNA polymerase activity distinguishable from host cell DNA polymerases by its high salt requirement for maximal activity. By column chromatography on DEAE-cellulose, DNA-cellulose, phosphocellulose, and hydroxyapatite, the EHV-1-induced polymerase was purified 500-fold with 1–2% recovery of total activity from the nuclei of infected hamster livers. The final enzyme preparation was homogeneous as judged by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Calculations based ...
Relationship of protein concentration and water content of equine serum and plasma samples. A highly significant correlation between the water content and protein concentration of equine serum and plasma samples was demonstrated over a wide range of concentrations. A close correlation was also observed between protein concentration as estimated by refractometry and as determined by the biuret procedure for equine serum and plasma samples.
Studies on cytochrome c. XIV. Synthesis of the protected heptadecapeptide (sequence 88-104) of horse heart cytochrome c. A solution synthesis is described of the partially protected N alpha-benzyloxycarbonylheptadecapeptide Z-Lys (Tfa)-Thr-Glu-Arg-Glu-Asp-Leu-Ile-Ala-Tyr-Leu-Lys (Tfa)-Lys (Tfa)-Ala-Thr-Asn-Glu (OBu t)-OBu t corresponding to sequence 88-104 of horse heart cytochrome c. The synthesis is achieved through the preparation of two subunits H1 (sequence 88-96) and H2 (sequence 97-104) and their linkage by an azide coupling step.
Stability of cephalosporins in horse serum. The antibiotic activity of cephalothin, cephaloridine, cephalexin, cephaloglycin, cefazolin, and cefamandole was determined after storage for up to 30 days in horse serum at -10 and 4 degrees C. Cephalothin, cefamandole, cefazolin, and cephalexin were stable for at least 30 days at -10 degrees C, whereas cephaloridine lost 29% of its initial activity and cephaloglycin lost more than 50%. Cefamandole, cefazolin, and cephalexin could only be stored for 3 days at 4 degrees C without significant loss in activity, whereas cephalothin, cephaloridine, and cephaloglycin could be stored for only 1 day....
Labeling of antilactose antibody. Affinity labeling studies with anticarbohydrate antibodies have been very limited. In earlier studies, diazoniumphenyl glycosides were employed as affinity labeling reagents for rabbit and equine anti-p-azophenyl-β-lactoside and p-azophenyl- β-galactoside antibodies. Although these antibodies were heterogeneous, it was possible to identify the labeled residues in the heavy or light chains since the modified residues had characteristic absorption spectra. With the discovery of bacterial cell walls of Streptococcus groups A and C induced antipolysaccharide antibodies of restricted heterogeneit...
Studies on cytochrome C. XIII. Synthesis of the protected undecapeptide (sequence 77-87) of horse heart cytochrome c. A solution synthesis of Z-Gly-Thr-Lys (Tfa)-Met-Ile-Phe-Ala-Gly-Ile-Lys (Tfa)-Lys (Tfa)-NHNH-Boc corresponding to the sequence 77-87 of horse heart cytochrome c is described. The protected undecapeptide was obtained from intermediate hepta- and tetrapeptide fragments by an azide coupling.