Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effect of pH change on the reconstitution of aspartate aminotransferase (EC 2.6.1.1), i.e. the reactivation of the apoenzyme with coenzyme (pyridoxal phosphate and pyridoxamine phosphate), was studied in the pH range 4.2-8.9 by using three buffer systems at concentrations ranging from 0.025 to 0.1m. 2. Although the profile of the reconstitution rate-pH curve in the range pH5.2-6.8 (covered by sodium cacodylate-HCl buffer) reflects the influence of the H(+) concentration on the reconstitution process, the profile of the curve in the pH ranges 4.2-5.6 and 7.2-8.25 (covered respectively by sodium acetate-acetic acid and Tris-HCl buffers) appears to be influenced by the ionic strength of the buffer. 3. The reconstitution is also influenced by univalent inorganic ions such as halide ions and, to a lesser extent, alkali metal ions, which are known to alter the water structure.
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PMID:Effect of pH, ionic strength and univalent inorganic ions on the reconstitution of aspartate aminotransferase. 485 93

During the transamination reaction of mitochondrial aspartate aminotransferase, transfer of tritium from the alpha-position of glutamate to the pro-S position of C4' of pyridoxamine 5'-phosphate was detected. A fast mixing and quenching device had to be used in order to reduce the number of transamination cycles undergone by the enzyme and thus to minimize the accompanying exchange of label with water. The extent of transfer of label (mean value 1.5%; range 0.8-4%) indicates that the 1,3-prototropic shift follows a stepwise rather than a concerted mechanism and that a single acid/base group is responsible for the proton transfer. The actual extent of proton transfer has to be much higher because the rate of alpha-tritium exchange with solvent was only approximately 10% of that of the turnover of unlabeled substrate, reflecting either an isotope effect or a retention of the tritium label in the reaction center during tautomerization. Under the assumption of an isotope effect, the actual transfer may be estimated to be 13%. This value is consistent with the notion of Lys-258 acting as the proton transferring group in which case the maximal value of transfer in an active site not accessible to solvent during the 1,3-prototropic shift would be 33%. However, alternative mechanisms involving Tyr-70 or a water molecule enclosed in the active site serving as acid/base group cannot be excluded on the basis of the present results. Furthermore, in these investigations aspartate aminotransferase was found to catalyze also the exchange of tritium from the beta-position of glutamate, though at a rate 350 times slower than that of the alpha-exchange.
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PMID:Transfer of C alpha-hydrogen of glutamate to coenzyme of aspartate aminotransferase during transamination reaction. 615 79

Serum chemical values were determined in cold-stressed Holstein bull calves ranging from 1 to 7 days of age. The animals were anesthetized and cold-stressed until their core body temperature (colonic) was lowered 10 C. Animals were then rewarmed in warm water, with heat pads or heat lamps, or were allowed to recover naturally (unassisted) at room temperature. Blood samples were collected at selected intervals during cooling and recovery. Increases (P less than 0.05) were observed in the concentrations of glucose, calcium, phosphorus, iron, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, total protein, albumin, total globulin, serum urea nitrogen, uric acid, total bilirubin, indirect bilirubin, and cholesterol in the cold-stressed calves during cooling. Concentrations of chloride and insulin decreased (P less than 0.05) during the same period. Changes observed in many of the serum chemical values during rewarming were generally the reverse of the respective changes that occurred during cooling, although insulin values became exceedingly high in some cases midway or near the end of recovery. Serum enzyme values also remained high during most of recovery. Data did not indicate a clear advantage of one method of rewarming over the other methods used in terms of return of the serum chemical values to normal.
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PMID:Serum chemical values in hypothermic and rewarmed young calves. 634 64

When aflatoxin-contaminated grain is consumed by dairy cows, aflatoxin M1 is excreted in the milk. Sixteen neonatal male Holstein calves were given milk which had been collected from cows given 5 to 6 mg of aflatoxin B1 each day. The calves were examined for possible detrimental effects of the mycotoxin at pseudophysiologic concentrations. Calves were allotted to 1 of 4 groups given different milk dietary aflatoxin M1 concentrations: group 1--given 0 microgram of aflatoxin M1/L (undetectable); group 2--given 0.5 microgram/L; group 3--given 1 microgram/L; and group 4--given 2 micrograms/L. Whole milk equal to 8% of body weight was fed daily and adjusted each week to maintain this ratio. Water and a 15% crude protein complete calf starter ration were offered ad libitum for the 6-week feeding study. Weekly blood samples were collected via jugular venipuncture and analyzed for serum alkaline phosphatase and aspartate aminotransferase activities. Daily means for milk dry matter intake (in kg) and complete ration intake (in kg) for the calf groups were as follows: 0.46 and 0.36 for group 1; 0.46 and 0.25 for group 2; 0.42 and 0.18 for group 3; and 0.49 and 0.40 for group 4. Significant differences in complete ration and total dry matter intake were noted. The average daily gains (in kg) and gains in height at withers (in cm) were 0.39 and 4.1 for group 1; 0.36 and 4.0 for group 2; 0.29 and 5.7 for group 3; and 0.42 and 5.1 for group 4.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of aflatoxin M1 intake at physiologic levels on newborn dairy calves. 643 98

Using mounting casein and wheat gluten protein values (0-40%) in the animals' diet, the optimum and minimum physiological daily doses were determined in 49-day-old growing rats from changes in their body water, body nitrogen and protein intake. The optimum physiological doses were identical with the peak of linearity of the given parameters, which coincided with a 15% casein protein and a 20% gluten protein concentration in the diet. This was also confirmed by the maximum body amino acid values, which were found in animals given a 15% casein or 20% gluten protein diet. It was further confirmed by the finding of significantly elevated alanine aminotransferase and aspartate aminotransferase activity in the liver of animals with a higher intake of the above protein sources. The minimum physiological dose of the given protein was determined from the equations of the regression curves in the presence of zero changes in the body nitrogen or body water content. The optimum physiological daily doses of casein and wheat gluten protein were 3.25 g and 4.05 g respectively. The minimum physiological daily doses of casein protein were 268 mg (from body nitrogen changes) and 371 mg (from body water changes) and the minimum physiological daily doses of gluten protein were 892 mg (from body nitrogen changes) and 1,000 mg (from body water changes). The above indicators demonstrate, in the presence of higher and high dietary concentrations, that an intake of the given proteins over and above the optimum physiological daily dose is at the very least uneconomical (gluten), if not harmful (casein), making this a highly topical problem for further study.
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PMID:Physiological casein and gluten protein requirements of growing rats. 648 24

Acute necrosis of R3230AC mammary tumor or thyroid carcinoma subcutaneously implanted in F344 rats was achieved by injection of a strongly hypertonic hexose and serotonin solution at 37 degrees C into and around the tumors. Changes in gross metabolism, hematology, and blood chemistry were then followed over a 9-day period, and they were most marked during or at the end of the first 24 hours. Food intake of the rats was sharply reduced, whereas drinking and diuresis were increased. Marked hemodilution and increased serum concentrations of aspartate aminotransferase, potassium, and uric acid were observed, as well as stable serum concentrations of sodium and chloride. Glucose overload, as opposed to fructose overload, led to secondary hypoglycemia. From day 2 food consumption returned to normal and increased thereafter. Water intake and urine output remained high. After an initial loss, body weight caught up with that of control rats. Hematocrit recovered partially, whereas blood chemistry progressively returned to about normal values.
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PMID:Systemic tolerance of osmotically induced oncolysis in rats. 657 33

Glutamate dehydrogenase activity in the liver of the rainbow trout increases when the animals are starved for four weeks. Glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in the kidney of rainbow trout kept in sea water (20% S) is significantly higher than in the kidney of rainbow trout kept in fresh water. Gill Na/K-ATPase activity in the rainbow trout is reduced significantly (44%) by starvation for four weeks. Most of the free amino acids investigated in the white muscle of the rainbow trout were present in significantly higher concentrations in animals fed in sea water than in animals fed in fresh water. The concentrations of these amino acids are even higher in the muscle of starved animals held in sea water than in fed animals held in sea water.
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PMID:Influence of nutrition on biochemical sea water adaptation of the rainbow trout (Salmo gairdneri richardson). 661 64

From 15 to 21 August 1981, Pontiac fever affected 317 automobile assembly plant workers. Results of serologic tests were negative for Mycoplasma, Chlamydia, respiratory tract viruses, and previously described legionellae. A gram-negative, rod-shaped organism (WO-44C) that did not grow on blood agar, required L-cysteine for growth, and contained large amounts of branched-chain fatty acids was isolated from a water-based coolant. The organism did not react with antisera against other legionellae, and on DNA hybridization the organism was less than 10% related to other Legionella species. Geometric mean titers found by indirect fluorescent antibody testing to WO-44C were significantly higher in ill employees than in controls (p = 0.0001). Attack rates by department decreased linearly with the department's distance from the implicated coolant system. The etiologic agent apparently was a new Legionella species; we propose the name Legionella feeleii species nova (AATC 35072). This is the first outbreak of nonpneumonic legionellosis in which the etiologic agent is not L. pneumophila, serogroup 1.
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PMID:A new Legionella species, Legionella feeleii species nova, causes Pontiac fever in an automobile plant. 669 54

Groups of four 6- to 12-month-old male goats were injected intraruminally with a lethal dose (3 mg/kg of body weight) of aflatoxin B1 (AFB1). Drugs were administered parenterally before (pretreatment) or beginning 8 hours after goats were doses with AFB1. These drugs were phenobarbital (PB), phenylbutazone (PBZ), piperonyl butoxide (PRO), benzoflavones, water, and 5% glucose solution (D5W). Most groups given the drugs after AFB1 was administered also were given intraperitoneal injections of methionine-sodium thiosulfate (MET-TS) solution. Clinical signs of toxicosis, serum aspartate aminotransferase activities, serum bilirubin concentrations, duration of illness, mortality, and gross and microscopic pathologic findings taken together indicated that toxicosis was increased with MET-TS + PB therapy, PBZ pretreatment, PBZ therapy, benzoflavone pretreatment, benzoflavone therapy, MET-TS + benzoflavone therapy, and MET-tS + water therapy. Toxicosis was not altered appreciably by MET-TS + PBO therapy. Beneficial effects (less severe toxicosis) were produced by PB pretreatment; these effects were prolonged maintenance of strength, vigor, and appetite and (in 1 goat that recovered) absence of pathologic changes or serum bilirubin increase. Therapy with MET-TS + D5W (but not MET-TS alone) also lengthened maintenance of strength, vigor, and appetite, but did not prevent pathologic changes. The beneficial effect of MET-TS therapy reported in a previous study (AFB2 dosage of 4 mg/kg) was not observed with the 3 mg/kg lethal dose. In conclusion, therapy for acute aflatoxicosis with inducers of hepatic microsomal enzymes is ineffective (PBO) or contraindicated (PB, PBZ, benzoflavones). Therapy with D5W may be a useful adjunct to other therapeutic drugs, but multiple intraperitoneal injections of D5W may decrease survival time because of stress.
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PMID:Effect of some enzyme inducers, fluids, and methionine-thiosulfate on induced acute aflatoxicosis in goats. 680 46

Male New Zealand White rabbits were treated with microsomal enzyme inducers, inhibitors of hemoprotein synthesis or action, and glutathione precursor and depletor before they were orally given the median lethal dose (LD50) of aflatoxin B1 (AFB1; 0.4 mg/kg) at the start of a 7-day experimental period. The drugs administered, mean duration of illness (hours), and survival percentage were as follows: controls (saline solution)-85, 50%; phenobarbital (PB)-100, 100%; phenylbutazone-115, 67%; benzoflavone-39, 17%; stanozolol-67, 67%; cobaltous chloride (CoCl2)-46, 67%; piperonyl butoxide (PBO)-88, 100% cysteine (CYS)-68, 100%; ethyl maleate-71, 83%. Signs of toxicosis included decreased feed and water consumption, weight loss, dehydration, lethargy, and emaciation; some rabbits died or were euthanatized. Clinico-pathologic changes included increased serum aspartate aminotransferase (AST) activity by 24 hours and bilirubin concentration by 48 to 72 hours after AFB1 was given. Grossly, livers were pale or tan and friable, with prominent lobular architecture. Kidneys of affected rabbits were pale to dark red. Microscopically, livers were normal or had lesions as great as extensive necrosis, hemorrhage, mineralization, and bile duct proliferation. Treatment of rabbits with PB, CoCl2, PBO, and CYS protected against AFB1 hepatic pathology, and PB, PBO, and CYS also had protective effect against lethality. Ethyl maleate provided some protection against lethality and increased serum AST activity and bilirubin concentration. Toxicosis was enhanced by benzoflavone; phenylbutazone and stanozolol had litte influence.
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PMID:Effect of enzyme inducers and inhibitors and glutathione precursor and depleter on induced acute aflatoxicosis in rabbits. 680 67


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