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Topic:Enzymes
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.
Preparation and some properties of a dimeric form (S-S) of horse muscle acylphosphatase. The use of sodium selenite as a catalyst in the presence of oxygen was a suitable technique to obtain in good yield an interchain S-S dimeric form of horse muscle acylphosphatase. The dimer so obtained possesses kinetic properties very similar to those of the native enzyme. On the other hand the dimer has shown a generally lower stability in respect of the thermal inactivation, particularly in the acidic environment, to the lyophilization and to the proteolytic attack. As regards the 8 M urea inactivation, the dimer is not able to completely regain its activity by dilution, showing a behaviour...
A comparative histochemical study of intrinsic laryngeal muscles of ungulates and carnivores. The intrinsic laryngeal muscles of the horse, donkey, sheep, ox, pig, dog and cat were examined for myosin ATPase, following acid and alkali pre-incubation, SDH and M-alphaGPDH activities. In all laryngeal muscles two fibre types, betaR and alphaR, belonging to slow and fast-contracting, fatigue-resistant motor units (types S and FR) were present in different proportions. The alphaW fibre type, belonging to fast-contracting and fatigue-resistant motor units was absent (type FF). The alphaR fibres of the dog and the cat were subdivided into groups by the various degrees of acid stable myosin AT...
Serum and liver lipid composition and lecithin: cholesterol acyltransferase in horses, Equus caballus. 1. The lipid composition of serum and liver and some properties of serum lecithin: cholesterol acyltransferase of the horse were investigated. 2. Phospholipids and cholesterol were the major components of serum lipids and the concentration of triglyceride was considerably low. The concentration of liver lipids was comparable with that of other mammals. 3. Fatty acid composition of serum cholesterol ester resembled that of the 2-position of lecithin, except palmitic acid. 4. The activity of serum cholesterol esterifying enzyme was found to be 0.03-0.09 mumol/hr per ml. There was an equimolar de...
Comparative studies on serum arginase and transaminases in hepatic necrosis in various species of domestic animals. Serum concentrations of arginase, glutamic pyruvic transaminase (SGPT) and glutamic oxaloacetic transaminase (SGOT) in dogs, cats, horses, cattle, sheep and pigs were determined before and after oral administration of CCl(4) at doses known to cause hepatic necrosis. Following CCl(4) administration, serum concentration of arginase and SGOT increased to a level of diagnostic significance in all animals. SGPT increased markedly in dogs and cats and marginally in 1 of 3 cattle and 2 of 3 pigs. In the surviving animals, the serum concentration of arginase returned to normal range much earlier than ...
A detection tube for cholinesterase inhibiting compounds. The enzyme butyrylcholinesterase from horse serum catalyses the hydrolysis of certain esters. The orange-red 2,6-dichloroindophenyl acetate will be converted by the enzyme into a deep blue alcohol. The colour transformation does not occur when the enzyme is inactivated. By making use of this biochemical reaction a cheap and simple, but very sensitive and specific detection tube could bedeveloped. The tube comprises a breakable ampoule with an aqueous buffer solution, a freeze-dried preparation of the chromogenic ester with a filler promoting its dissolution, a freeze-dried preparation of butyr...
Isoelectric focusing of some enzymes from Echinococcus granulosus (horse and sheep strains) and E. multilocularis. Extracts of the horse and sheep strains of Echinococcus granulosus and E. multilocularis were compared on the basis of their isoenzyme patterns for 10 enzymes by means of isoelectric focusing in polyacrylamide gels. The enzymes examined were: acid phosphatase, lactate dehydrogenase, malate dehydrogenase, malic enzyme, phosphoglucoseisomerase, isocitrate dehydrogenase, adenylate kinase, aldolase and alpha-glycerophosphate dehydrogenase. Interspecific and intraspecific differences are apparent in the isoenzyme profiles of all the enzymes except adenylate kinase; the pattern and activity of adeny...
Differences in the histochemical properties of skeletal muscles of different breeds of horses and dogs. Histochemical profiles of individual muscle fibres were established using myosin adenosine triphosphatase (myosin ATPase), succinate dehydrogenase (SDHase), and glycogen phosphorylase (GPase) reactions in three muscles (semitendinosus, diaphragm, and pectoralis transversus) of the horse and dog. The major histochemical difference between fibres lies in their myosin ATPase activity; fibres can be subdivided into those with a high and those with a low activity. In horse muscle, all fibres have a high activity of GPase. In the diaphragm and pectoralis transversus, all fibres have a high SDHase ac...
A study of the specificity of Bandeiraea simplicifolia lectin I by competitive-binding assay with blood-group substances and with blood-group A and B active and other oligosaccharides. The specificity of Bandeiraea simplicifolia lectin I (BS I) has been studied by competitive-binding assays (CBA) using tritium-labeled human B and hog A substances. Blood-group B substances isolated from horse gastric mucosae and from human ovarian-cyst fluids were much better inhibitors of binding of tritiated blood-group B substance to insoluble BS I-Sepharose 2B than were human blood-group A substances from saliva and ovarian-cyst fluid. A and B active blood-group substances showed the same range of potency in inhibiting binding of tritium-labeled hog A substance to BS I-Sepharose 2B. CBA w...
Alkaline isomerization of horse and yeast cytochromes C. Spectrophotometric and circular dichroism studies. Spectrophotometric studies of the alkaline isomerization of horse heart and yeast cytochrome c show that the haemoproteins from Saccharomyces cerevisiae differ significantly from the mammalian cytochrome c. Apparent pKa values of 8.41, 8.40 and 8.73 for isol-1-(the methylated and unmethylated forms) and iso-2-cytochrome c respectively, from baker's yeast were determined and compared with the value of 9.40 found for horse heart cytochrome c. The transitions, measured by observing the decrease of the absorbance at 695 nm as the pH increases, have been found to strictly parallel the decrease in a...
The presence of two (Na+ + K+)-ATPase inhibitors in equine muscle ATP: vanadate nad a dithioerythritol-dependent inhibitor. A potent inhibitor of (Na+ + K+)-ATPase activity was purified from Sigma equine muscle ATP by cation- and anion-exchange chromatography. The isolated inhibitor was identified by atomic absorption spectroscopy and proton resonance spectroscopy to be an inorganic vanadate. The isolated vanadate and a solution of V2O5 inhibit sarcolemma (Na+ + K+)-ATPase with an I50 of 1 micrometer in the presence of 1 mM ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA), 145 mM NaCl, 6mM MgCl2, 15 mM KCl and 2 mM synthetic ATP. The potency of the isolated vanadate is increased by free Mg2+. ...
Direct colorimetric determination of serum arginase in various domestic animals. A direct colorimetric method for the determination of serum arginase activity in various domestic animals is described. Serum arginase activity in healthy mature dogs, cats, horses, cattle, sheep, and pigs ranged from 0 to 14 IU/L. Serum arginase activity increased considerably in these animals during experimental hepatic damage induced by oral administration of carbon tetrachloride.
Blood and tissue content of the iso-enzymes of lactate dehydrogenase in the thoroughbred. The occasions, position and relative concentration of LDH iso-enzymes in the blood tissues of the thoroughbred horse were determined. Locomotor muscles possess a high concentration of LDH 5 whereas non-locomotor muscles have a low concentration of this iso-enzyme.
Analysis of mechanisms regulating the expression of parental alleles at the GPD locus in mule erythrocytes. Erythrocyte glucose-6-phosphate dehydrogenase (G6PD) was examined by 13% starch gel electrophoresis in 74 mules (42 females and 32 males), 35 donkeys, and ten horses. The quantitative expression of the parental alleles at the Gpd locus varies greatly in female mules from the hemizygous expression of the maternal allele to that of the paternal. The data obtained indicate that the X chromosomes are randomly inactivated in females mules. No selective advantage of a cell population with a maternally (or paternally) derived X active was found in female mule erythrocytes. It is suggested that the ph...
Further characterization of Listeria monocytogenes serotype 5. Fifteen strains of Listeria monocytogenes serotype 5 were characteriized for carbohydrate utilization, enzymic reactions, and other differential criteria. Hemolytic patterns were tested on ovine, bovine, equine, human and lapine blood agars. Results were compared with those of previously reported strains of L. monocytogens serotype 5.
Circular dichroic properties and conformation of thionicotinamide dinucleotides bound to horse-liver alcohol dehydrogenase. The interaction between horse liver alcohol dehydrogenase and the oxidized and reduced forms of the 3-thionicotinamide--adenine dinucleotide coenzyme analogues (sNAD and sNADH) has been investigated by ultraviolet absorption, fluorescence and circular dichroism. The fluorescence of sNADH is enhanced when bound to the enzyme, and the protein fluorescence is quenched by both sNADH (60--65%) and sNAD (65%). The possible origin of the larger quenching produced by sNAD with respect to that of NAD is discussed. Coenzyme dissociation constants have been determined by monitoring the quenching of the p...
Blood glutathione peroxidase activity in horses in relation to muscular dystrophy and selenium nutrition. The activity of glutathione peroxidase, a selenium containing enzyme, was measured in the blood of horses to determine its usefulness as an indicator of selenium status. In 15 horses the enzyme activity was positively related to the blood selenium concentration (P less than .001, r-0.98) over the range of enzyme activities of 8.2 to 140 units (mumoles NADP-oxidised/min/gHb) and selenium concentrations of 0.24 to 2.74 mumol/l. In a group of 8 horses which 2 foals had died with lesions of muscular dystrophy the enzyme activity increased from a mean of 11.8 units before treatment with selenium to...
[Immunochemical investigations on the gene expression of horse serum carboxylesterase (author’s transl)]. Immunochemical and enzymatic analyses of horse serum carboxylesterase were carried out with respect to the existence of a silent gene. Sera with positive phenotypic expression of esterase, both heterozygotes and presumed homozygotes, were compared with:--sera with positive phenotypic expression but genotypically +/O;--sera with a negative phenotypic expression, i. e. genotypically O/O;--sera of natural +/O "hemi-zygotes": mules (donkey lacking the esterase);--positive sera heated at 60 degrees C;--positive sera after specific inhibition of enzymatic activity. Titration by immunocompetition has...
Stability of horse muscle acylphosphatase to heat and to urea. The thermal stability of horse muscle acylphosphatase was investigated by measuring the inactivation constants at various pH and temperature values, and by differential spectra technique. This enzyme has high thermal stability in an acidic environment but is inactivated in an alkaline medium. It was found that the enzyme can be protected against such inactivation at pH 8.0 by increasing its concentration and the ionic strength of the solution. The effect of high urea concentrations on stability was also measured. It was found that spectral changes at 230 nm are related to urea inactivation of ...
Stability and kinetic behavior of carboxymethylated horse muscle acylphosphatase. Horse muscle acylphosphatase consists of a main chain S-S bound to glutathione. It was found that removal of the glutathione by reduction and successive carboxymethylation of the only cysteine of the main chain affects the stability of the enzyme, mainly with respect to thermal inactivation. On the other hand, the kinetic properties of the enzyme are affected very little.
[Comparative study of the muramidase (lysozyme) activity in the blood cells of laboratory and agricultural animals]. Comparative studies have been carried out on the blood of certain laboratory and farm animals and birds, whereby the activity of muramidase (lysozyme) is established in neutrophilic cells of mice, guinea pigs, rats, rabbits, dogs, hens, turkeys and geese and in the monocytes of rabbits and dogs. The percentage of cells with muramidase activity manifests species features. No cells with a presence of muramidase activity have been found in the perypheral blood of cattle, sheep, pigs, goats, horses and bullalos. Certain questions of a general biological aspect about the origin of muramidase in the...
Isoelectric focusing of horse serum esterase isozymes and detection of new phenotypes. A new method for separating the isozymes of horse serum esterase is described. The improved resolution has enabled us to detect several previously undescribed phenotypes. This method has also been used to detect two different apparently 'silent' alleles.
Common and species-specific esterases of Equidae–IV. Horse of przewalski, onager and Zebra hartmannae. 1. Among several species of Equidae only E. przewalskii possesses a serum esterase identical with that of E. caballus. 2. The esterases of Hemionidae differ slightly from that of domestic horse by electrophoretic migration and by antigenic structure. 3. Zebras (grevyi, burchelli) appear devoid of this component but Z. hartmannae possesses an esterase of high enzymatic activity, differing notably from that of horse by electrophoretic and antigenic properties.
Comparative studies on blood serum alpha-L-fucosidases from several mammalian species. 1. Peripheral blood serum alpha-L-fucosidases have been studied from various mammalian species: Sus scropha var domestica L. (pig), Capra hircus L. (goat), Bos taurus L. (bull, races Morucha and Charolais), Equus caballus L. (horse) and Equus asinus L. (donkey). 2. Fluorimetric and spectrophotometric procedures were used for determination of alpha-L-fucosidases. 3. alpha-L-Fucosidases were more active towards fluorescent substrates than towards chromogenic substrates. 4. pH optima values of the enzymes are: (A) 5.5 for sera from all above-mentioned species when fluorescent substrates were empl...
The null allele in the horse esterase (Es) system detected by enzyme assay and rocket immunoelectrophoresis in heterozygous animals. The detection of the recessive null allele of horse serum esterase (Es) is possible in heterozygotes Es+/EsO which by starch gel electrophoresis appear like homozygotes Es+/Es+. Two methods are proposed, the titration of enzymatic activity of esterase and the immunochemical titration of esterase as antigen. These methods can be applied to solve the cases of suspect parentage or in population studies.
