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.
Serum and intracellular retinol in the equine. 1. Serum and intracellular distribution of retinol was determined in equines maintained on four levels of vitamin A intake. 2. The form of retinol transported in serum was determined by gel filtration and chromatography to be a complex of retinol bound to a protein of molecular weight (MW) of approximately 20000, which was in turn complexed probably with prealbumin to yield a complex with a MW of 75000 to 80000. 3. Increasing dietary vitamin A levels enhanced the concentration of lipoprotein-bound retinyl esters in the plasma. 4. Vitamin A in the liver cytosol was found predominantly as retiny...
Milk production of quarter horse mares during 150 days of lactation. Milk production was measured in fourteen Quarter Horse mares at seven stages of a 150-d lactation period. Mares were divided into two groups of seven and fed diets containing either soybean meal or soybean meal and urea as nitrogen supplements. Rations were isocaloric, contained approximately 12.5% crude protein and were fortified with vitamins and minerals. Daily milk yield was estimated by the weigh-suckle-weigh method and milk composition was determined from samples taken by hand milking. Average daily milk yield ranged from 11.8 kg in early lactation to 9.8 kg in late lactation. Difference...
Renal dysfunction in a case of purpura haemorrhagica. A four-year-old thoroughbred was presented with clinical manifestations of purpura haemorrhagica. Evidence of renal involvement consistent with glomerulopathy and nephrotic syndrome, characterized by heavy proteinuria and azotaemia, became apparent and may have been exacerbated by diuretic therapy. Autopsy revealed membrano- and mesangial proliferative glomerulonephritis and chronic pleuritis. Circulating immune complexes may have been responsible for the renal diseases and the purpura.
Purification of horse eosinophil peroxidase. Eosinophil peroxidase (donor: hydrogen-peroxidase oxidoreductase, EC 1.11.1.7) was isolated in a highly purified form (415/280 nm ratio, 1.05) from horse peripheral blood eosinophil. Eosinophil peroxidase was extracted from intact eosinophils (98-100% purity) or isolated eosinophil granules with 0.05 M acetate buffer (pH 4.7)/0.18 M NaCl and purified by chromatography on Sephadex G-200 and carboxymethylcellulose. Final elution was with 0.05 M acetate buffer (pH 4.7)/ 1 M NaCl. Horse eosinophil peroxidase is a strongly basic protein with bacterial properties when combined with H2O2 and iodide, ...
Renal dysfunction in a case of purpura haemorrhagica in a horse. A four-year-old thoroughbred was presented with clinical manifestations of purpura haemorrhagica. Evidence of renal involvement consistent with glomerulopathy and nephrotic syndrome, characterised by heavy proteinuria and azotaemia, became apparent and may have been exacerbated by diuretic therapy. Autopsy revealed membrano- and mesangial proliferative glomerulonephritis and chronic pleuritis. Circulating immune complexes may have been responsible for the renal diseases and the purpura.
Analysis of equine thoracic fluid. Eighteen clinically normal horses were used to study the characteristics of normal thoracic fluid. Thoracic fluid was obtained from each horse and was found to be similar to equine abdominal fluid. Total leukocytes averaged 3994/ul, total protein 1.8 g/dl, and specific gravity 1.015. Analysis of thoracic fluid from 16 horses with clinical signs of thoracic disease showed abnormalities in every case. Thoracic fluid analysis alone determined a specific diagnosis in 50% of the cases.
Purification of horse muscle acylphosphatase antibodies by affinity chromatography. Horse muscle acylphosphatase antibodies were obtained by immunizing rabbits with the highly purified antigen cross-linked with glutaraldehyde. Specific antibodies were purified from the immunoglobulin fraction by affinity chromatography using a matrix coupled with the pure antigen as immunoadsorbent. The purified antibodies were partially characterized by immunodiffusion and immunoprecipitin techniques. These antibodies could be used to study aspects of the muscle acylphosphatase structure, localization and other biological properties.
[Purification of alpha-1,4 leads to 1,4-glucosyltransferase from horse blood serum]. The purification of alpha-1,4-1,4-glucosyltransferase from the equine serum is presented. Ion-exchange chromatography on DE-11, DE-32 and CM-32 celluloses was applied in the successive steps of isolation. Gel-filtration on Bio-Gel P-200 was the last step of purification; it gave the protein which was homogeneous on disc polyacrylamide gel electrophoresis. The purification degree was of the order 2100 at about 40% yield.
[Properties of alpha-1,4 leads to -glucosyltransferase from the muscles and blood serum of horses]. Alpha-1,4 leads to 1,4-glucosyltransferase preparations from horse muscles and serum were studied. The enzyme proteins from both tissues are very similar. Both proteins have a molecular weight of 240 000 and consist of four subunits of 60 000 daltons each. pH 5,0 is optimal for the activity. Only substrates with alpha-1, 4-linkages can serve as glucosyl donors for transferase reactions. Km values for both enzymes differ very slightly. At low substrate concentrations the hydrolytic activity can be found in addition to transferase reactions. At the concentration of the substrate higher than 40 m...
Isolation and some properties of equine alpha 1-antitrypsin. 1. Equine alpha 1-antitrypsin was isolated from horse plasma by a combination of ammonium sulfate and acidification precipitation followed by ion-exchange chromatography on DEAE-cellulose, molecular sieve chromatography on Sephadex G-200 and affinity chromatography on Cibacron Blue-agarose. 2. The purified protein showed a single precipitin arc on immunoelectrophoresis in agarose but gave two bands on discontinuous polyacrylamide gel electrophoresis (PAGE). 3. Both bands appeared to interact equally with trypsin and were thought to represent two isoinhibitors of equine alpha 1-AT.
Primary structure of horse erythrocyte glycophorin HA. Its amino acid sequence has a unique homology with those of human and porcine erythrocyte glycophorins. The complete amino acid sequence of the major sialoglycoproteins of horse erythrocyte membranes, glycophorin HA, was determined by manual sequencing methods, using tryptic, chymotryptic, and cyanogen bromide fragments. Glycophorin HA is a polypeptide chain of 120 amino acid residues and contains 10 oligosaccharide units attached to the amino-terminal side of the molecule. Its amino terminus is pyroglutamic acid. All of the oligosaccharides are linked O-glycosidically to threonine or serine residues. The amino acid sequence is consistent with the transmembrane orientation of glycophorins. There...
Comparison of receptor properties of erythrocyte membrane glycoproteins. Membrane glycoproteins from horse, sheep, goat and bovine erythrocytes were solubilized and purified. These glycoproteins could be placed in three groups based on their degrees of glycosylation: The major bovine erythrocyte glycoprotein (BGII) had 77% sugar, the minor bovine glycoprotein (BGI) had 27% sugar and the others had approximately 50% sugar. Four of the glycoproteins aggregated in a uniform way in aqueous solution--one, BGII, did not. Four had similar subunit sizes of 25-34,000 daltons, but BGII was larger--55,000 daltons. Receptor functions (for plant and invertebrate lectins, antibo...
Identification of stage-specific and hormonally induced polypeptides in the uterine protein secretions of the mare during the oestrous cycle and pregnancy. Uterine secretions were obtained on Days 4, 8, 12, 14, 16, 18 and 20 of the oestrous cycle and early pregnancy. Acid phosphatase activity was significantly affected by day of the cycle, reaching a maximum at days 12-14 during the luteal phase and then declining to almost undetectable levels, by Day 20. In pregnant animals, activity continued to increase beyond Day 14. Two-dimensional polyacrylamide gel electrophoresis showed that albumin was a major component. However, a number of unique proteins of non-serum origin appeared in mid-cycle but had disappeared by Day 20. One of these was a basic ...
Studies on the composition and antibacterial activity of uterine fluid from mares. Forty uterine fluid samples were obtained during oestrus and dioestrus of successive cycles from 4 mares classified as resistant to bacterial infection of the uterus. The flushings were assayed for peroxidase activity and ability to influence phagocytosis by polymorphonuclear neutrophils. Uterine fluid volumes and protein concentrations and serum oestrogen values were similar during oestrus and dioestrus. Serum progesterone concentrations were depressed during oestrus. Equine neutrophils adherent to glass slides were exposed to a genital strain of Streptococcus zooepidemicus suspended in salin...
Metabolism of purine nucleosides and phosphoribosylpyrophosphate in thymocytes and splenocytes of various mammalian species. 1. Activities of ADA, PNP and AK were measured in splenocytes and thymocytes of newborn children, young horses, pigs, sheep, rats and mice and compared with the activities previously found in peripheral lymphocytes. 2. With all species, except horse, the activity of ADA (per 10(6) cells) was higher in thymocytes than in lymphocytes. Activity of ADA was highest in splenocytes of pig and sheep. Activity of ADA was lowest in all lymphoid cells of the horse and only about 10% of the activity in human splenocytes and lymphocytes. 3. With all species, except horse, the activity of PNP was lower in t...
Cibacron Blue-induced modification of neutral proteinase from horse blood leukocytes. The proteolytic activity of the elastase-like proteinase from granules of horse blood leukocytes is retained on a column of Cibacron Blue-Sepharose and can be eluted with 0.5 M KSCN. During this procedure its mol. wt. is reduced from 49000 to 30000 and isoelectric point is shifted towards higher pH. The inactive protein not adsorbed on Cibacron Blue-Sepharose is strongly acidic and shows a mol. wt. of 20000. Upon mixing this protein with the modified enzyme the native proteinase is reconstituted as shown by polyacrylamide gel electrophoresis at pH 8.3 and isoelectric focusing in a sucrose grad...
Limited trypsinolysis of porcine and equine colipases. Spectroscopic and kinetic studies. Porcine and equine colipases have been submitted to mild tryptic digestion. Proteolysis occurs at the Arg5-Gly6 bond with the loss of the N-terminal pentapeptide. Studies of native and trypsin-treated colipases by circular dichroism and laser chemically induced dynamic nuclear polarization indicate that proteolysis induces conformational changes in the region of the tyrosine cluster. Experiments in the presence of phospholipid provide further evidence showing that these residues are in or close to the region of the protein interacting with aggregated lipids. Kinetic studies of the reaction of ...
Lysine supplementation of diets for yearling horses. Forty-six Thoroughbred and Quarter Horse yearlings were used in two experiments designed to determine the amount of lysine in the concentrate necessary to promote maximum growth when fed the Coastal bermudagrass (Cynodon dactylon) hay provided at 1% body weight (BW)/day. In the first experiment, a 196-day trial, supplemental protein sources and analyses of the concentrates compared were: (1) soybean meal (SBM; 15.4% crude protein, .70% lysine); (2) SBM + .2% lysine (15.7% crude protein, .81% lysine), and (3) brewers dried grains + .2% lysine (15.9% crude protein, .59% lysine). Concentrate inta...
Primary structure of 3-phosphoglycerate kinase from horse muscle. I. Purification of cyanogen bromide peptides and amino acid sequence of peptide CB5 (104 residues). 3-Phosphoglycerate kinase was isolated from horse muscle and subjected to the action of cyanogen bromide. The resulting peptides were separated using gel filtration combined with either ion exchange chromatography on phosphocellulose in 6 M urea or high voltage paper electrophoresis. The sequence of the largest peptide, CB5, has been determined by a combination of automated and manual Edman degradation carried out on the intact peptide and derivatives obtained by proteolytic digestion. The isolation of two peptides derived from CB5 by cleavage of the bond between Asp109 and Pro110 facilitated ...
Haematological changes during development of acute laminitis hypertension. Experimental carbohydrate overload of 15 horses resulted in consistent haematological changes during development of laminitis hypertension. Significant alterations in packed cell volume, leucocyte differential count, serum glucose levels and protein values occurred before onset of Obel grade 3 lameness and hyperkinetic circulatory state. Blood platelets were significantly decreased 8 h after the onset of severe lameness. Findings in this study were indicative of haemoconcentration due to compartmental fluid shifts and leucocytic stress response consistent with increased circulating adrenogluco...
Antigenic and structural conservation of herpesvirus DNA-binding proteins. Previously, we have shown a common antigen of several herpesviruses (pseudorabies virus, equine abortion virus and bovine mammillitis virus) to be antigenically related to the major DNA-binding proteins of herpes simplex virus types 1 and 2. In this study we have purified the cross-reacting polypeptide from cells infected with pseudorabies virus, equine abortion virus and bovine mammillitis virus and shown the cross-reacting protein to be a major DNA-binding protein for each virus. Tryptic peptide analysis of the cross-reacting DNA-binding proteins of all five viruses has shown structural simi...