Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kinetics of the interaction between deionized supernatant aspartic aminotransferase and various anions (cacodylate, phosphate and chloride) were studied by the temperature-jump technique. The anion concentration in the range covered by our experiments does not affect the transamination rate. On the other hand the conformational transition, recently observed at the active site of the enzyme, is hindered by an excess of anions. A single relaxation effect was observed at the enzyme chromophore wavelength in systems containing the aldimine form of the enzyme and the above anions. It is shown that this effect corresponds to the protonation of the chromophore. The relaxation times were of about 10 mus with phosphate, 20-100 mus with cacodylate and 1-2 ms with chloride. The pH and concentration dependence of this effect were studied. The fits of experimental data to a rate equations for various models were tested by a chi2 analysis. The best fit was obtained with models where anions bind rapidly to a site close to the chromophore, so that the pK of the chromophore is affected by anions binding. The rate of the observed relaxation considerably increased when the anion has buffering capacities; this indicates, in the case of cacodylate and phosphate, that the acidic component of the buffer directly exchanges a proton with the enzyme chromophore.
Eur J Biochem 1976 Dec 11
PMID:Kinetics of the interaction between aspartic aminotransferase and anions. 1 67

A middle-aged adult male with a mild form of tyrosinemia II (Richner-Hanhart syndrome) is described. Treatment with a low-tyrosine diet caused a fall in plasma tyrosine and clearing of the hyperkeratosis of the soles. Liver biopsy of this patient revealed low but measurable levels of cytoplasmic tyrosine aminotransferase and elevated levels of the mitochondrial tyrosine-metabolizing enzyme aspartate aminotransferase. It is hypothesized that these enzymes have been induced in sufficient amounts to account for the mild clinical course.
J Invest Dermatol 1979 Dec
PMID:Hepatic enzymes of tyrosine metabolism in tyrosinemia II. 4 76

A prospective study of 181 patients suspected of having liver disease was carried out to determine the relative efficiencies of serum bilirubin (total and direct), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with respect to diagnosis. Liver biopsies, liver scans, abdominal ultrasound, and clinical parameters were also tabulated and used independently to evaluate the patient's hepatic status and to determine the final diagnoses in each case. From the results of these tests for the 60 patients who were diagnosed as having liver disease, and the 87 patients who were felt to be free of liver disease, predictive values of the above tests were established. Data from this study suggests that while direct bilirubin is the most specific test, GGT is the most sensitive and has the fewest false negatives in the diagnosis of liver disease.
Clin Biochem 1979 Dec
PMID:Predictive values of various liver function tests with respect to the diagnosis of liver disease. 4 85

A comparison of the cost of laboratory-made reagents with that of commercial kits was made for three serum-enzyme estimations and three serum-hormone estimations. The cost of reagents in kit form could only be justified on economic grounds for serum aspartate transaminase, alanine transaminase, and lactic dehydrogenase if the laboratory performed less than about 35 tests per day. It is unlikely that the use of kits for serum tri-iodothyronine, thyroxine, and thyrotrophic hormone can be justified on economic grounds for any workload. It is estimated that between 2 million pounds and 3 million pounds is spent unnecessarily by the National Health Service each year to purchase commercially prepared reagents for the six tests studied.
Lancet 1977 Dec 17
PMID:Comparison of cost of preparing reagents in laboratory with cost of using commercial kits. 7 63

Intravenous administration of the rare earth metal salt, praseodymium nitrate, induced hepatic damage in the rat, as assessed by morphologic examination (light and electron microscopy) and biochemical parameters (serum glutamic-pyruvic transaminase (EC 2.6.1.2) and glutamic-oxalacetic transaminase (EC 2.6.1.1) activity as well as hepatic triglyceride content). Praseodymium hepatotoxicity was only attained with lower doses (10, 20, or 40 mg/kg), whereas a larger dose (80 mg/kg) was inactive in this respect. As detected by electron microscopy, lower doses of the metal salt caused hepatocytic alterations consisting of degranulation and dilatation of rough endoplasmic reticulum, accumulation of smooth endoplasmic reticulum as well as numerous lipid droplets. No abnormalities were detected in the cell organelles following administration of a large dose of the metal salt; however, vacuoles containing markedly electron-dense material were seen in the cytoplasm of the hepatocytes and the sinusoidal Kupffer cells.
Can J Physiol Pharmacol 1976 Dec
PMID:Effect of praseodymium nitrate on hepatocytes and Kupffer cells in the rat. 19 Nov 66

Lactate production by liver slices from fetal rats (17th--18th day of gestation) is enhanced about two fold by aminooxyacetate, an inhibitor of aspartate transaminase (EC 2.6.1.1). Such an effect is consistent with an increase of the cytosolic NAD-redox state owing to the parallel fall in the pyruvate level, whereas the glycolytic flux does not seem to be influenced appreciably. Indeed, although the inhibitor causes a marked increase of fructose 1,6-diphosphate, glucose-6-phosphate decreases only slightly. These results suggest that in fetal rat liver the malate-aspartate shuttle is operative in the reoxidation of cytosolic NADH produced during aerobic glycolysis.
Biochim Biophys Acta 1977 Dec 23
PMID:The operation of the malate-aspartate shuttle in the reoxidation of glycolytic NADH in slices of fetal rat liver. 20 12

The effect of daily dermal spray of malathion for four weeks in recommended (0.5 and 1.0 per cent) and higher (5.0 per cent) concentration on various enzymes in Bubalus bubalis species were studied. The higher concentration of 5.0 per cent showed lethal effect after 2 to 3 exposures. The cholinesterase activity in both RBC (RChE) and plasma (PChE) were inhibited with all the concentrations. There was also significant (P less than 0.05) elevation in the activities of serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase with 1.0 and 5.0 per cent spray and enzyme activities remained altered even during post-medication. The extent of various biochemical changes were dose and time dependent.
Bull Environ Contam Toxicol 1978 Dec
PMID:Influence of malathion (O,O'-dimethyl dithiophosphate of diethyl mercaptosuccinate) on body enzymes in dermal subacute toxicity studies in Bubalus bubalis species. 21 25

Perfused livers isolated from rats under halothane anaesthesia produced greater amounts of bile, released smaller amounts of aspartate aminotransferase, and had a much greater ability to maintain a constant concentration of glucose in perfusates than those obtained with ether or pentobarbitone. Little or no effect was shown on the ability of the liver to synthesize urea and to retain potassium within the organ. It appears, therefore,that halothane is the anaesthetic of choice when removing the liver from the laboratory rat.
Aust N Z J Surg 1979 Dec
PMID:Isolated liver perfusion: the choice of anaesthetic. 29 68

Forty-two consecutive patients were observed with the use of various biochemical and physiologic parameters. Attention was focused upon liver function, using serum glutamic-oxalacetic transaminase, alkaline phosphatase and bilirubin determinations as well as the plasma disappearance rate of indocyanine green. No difference was noted in serum glutamic-oxalacetic transaminase, alkaline phosphatase and bilirubin levels between survivors and nonsurvivors. However, there was a significant difference between these two groups as measured by the plasma disappearance rate of indocyanine green. A distinct cut-off point was present, and no survivor ever had a plasma disappearance rate of less than 6 per cent per minute.
Surg Gynecol Obstet 1979 Dec
PMID:Indocyanine green clearance in critically ill patients. 38 3

Normotensive, Sprague-Dawley (S-D) and spontaneously hypertensive (SH) rats were subjected to aortic ligature. The systolic blood pressure of S-D rats was increased by +/- 80 mm Hg, whereas the blood pressure of SH rats with pre-existent hypertension increased only slightly, +/- 9 mm Hg. The S-D rats developed myocardial and renal infarcts as well as polyarteritis nodosa; the SH rats developed testicular and microadrenocortical infarcts only. Aortic-ligated S-D rats had elevated creatine phosphokinase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, and lactic hydrogenase levels and manifested hyperglycemia, hypercholesterolemia, and elevated blood urea nitrogen (BUN) levels. Corticosterone levels increased in aortic-ligated S-D rats but decreased in SH rats. Collateralization about the site of aortic ligature appeared to be the same in both strains. It is suggested that the acutely induced hypertension in S-D rats rather than SH rats and differences in adrenal steroidogenesis between the two strains would best account for the dichotomous cardiovascular response to aortic constriction.
Am J Pathol 1979 Dec
PMID:Diverse cardiovascular responses to aortic constriction in normotensive Sprague-Dawley versus spontaneously hypertensive rats. 50 90


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