Aspartate amino transferase

EPEC = Enteropathogenic E. coli NA = not applicable UTI = urinary tract infections AST = aspartate amino transferase. Indicates studies that documented a substantial number of cases of bacterial diarrhea denotes studies with substantial isolation of bacterial enteropatho-gens. 1 Nonclassic enteric flora includes E. coli with the designation of enteropathogenic E. coli or other recognized diarrheogenic E. coli, Klebsiella, Proteus, Entero- bacter, Pseudomonas and Enterococcus. ... 

Hepatic Effects. A study that measured levels of several liver enzymes (alanine amino transferase, aspartate amino transferase, gamma glutamyl transferase, and alkaline phosphatase) found no significant differences between workers exposed to silver and insoluble silver compounds and those with no history of silver exposure (Pifer et al. 1989). 

A combination of D-amino acid oxidase and L-amino transferase is an example of a deracemization by stereoinversion. The product is an L-amino acid. The reaction catalyzed by amino transferase has an equilibrium constant close to unity, a very unpractical situation leading to uncomplete transformation and to the production of almost inseparable mixtures of amino acids (at least two, the amino acid product and the amino add used as an amino donor). For preparative purposes it is therefore mandatory to shift the equihbrium to the product side. A recent example of a deracemization procedure based on this coupled enzymatic system is the preparation of L-2-naphthyl-alanine 6 as illustrated in Scheme 13.9 [28]. The reaction occurs in one pot with initial oxidation of the D-amino acid catalyzed by D-amino acid oxidase from Rhodotonda gracilis. The hydrogen peroxide that is formed in stoichiometric amounts is decomposed by catalase. The a-keto add is the substrate for L-aspartate amino transferase (L-Asp amino transferase), which is able to use L-cysteine sulfinic acid 7 as an amino donor. 

The most commonly used L-amino transferase activities for L-amino acid synthesis are the ones from E. coli, which can be used in whole cell or immobilized systems. They include the following. First, aspartate amino transferase (EC 2.6.1.1), the... 

Murphy et al. (1964) found increased activities of alkaline phosphatase in livers of rats exposed to 35 ppm formaldehyde for 18 hours and suggested that formaldehyde may be hepatotoxic. More recent animal studies, however, have found no consistent evidence for formaldehyde-induced hepatotoxicity. Woutersen et al. (1987) found statistically significant increased levels of aspartate amino transferase, alanine amino transferase, and alkaline phosphatase in plasma of rats exposed to 20 ppm, (but not to 10 or 1 ppm) 6 hours/day, 5 days/week for 13 weeks, but found no exposure-related microscopic lesions... 

The mechanism by which an enzyme catalyzes its specific reaction is known in varying levels of detail in a number of cases, for example, rihonuclease, lysozyme, serine proteases, carboxypeptidase, aspartate amino transferase, and lactate dehydrogenase. The mechanisms differ, but some useful general principles have emerged from studies of individual enzymes. Enzymes use the normal principles of organic chemistry. 

Alanine aminotransferase (ALT) and aspartate amino transferase (AST) are released from the liver when liver cells are injured. Measurement of these two transaminases in the serum (ALT and AST) is one of the standard laboratory tests for liver damage caused by a variety of conditions. 

Prasad et al. [191] based their CDT calculation of Tf separated by CZE on the ratio of the area of disialo-Tf (they did not detect asialo-Tf) to the area of total Tf in the sample. On the basis of this index and with a control population of social drinkers, they established a CDT cutoff value. This cutoff value was exceeded by the majority of alcohol abusers studied. This CDT measurement was compared with other alcohol abuse markers (e.g., aspartate amino transferase, alanine amino transferase, and others) and it was found to be the most specific one. 

Even with high M.W. enzymes labeling coenzyme e.g. ( CHO-PLP) can give excellent results. Thus the use of C-labeled coenzyme in the reactions catalyzed by cytosolic aspartate amino transferase (EC 2.6.1.1) a dimeric protein (Mj. 90,(XX)), allows clear observation of both internal and external aldimine forms with inhibitors such as methyl aspartate as shown in Fig. 13 [9]. 

Gout patients also underwent investigation of liver function by estimation of serum bilirubin, alkaline phosphatase, aspartate amino transferase and bromosulphthalein retention The last mentioned investigation was performed by the intravenous injection of 5nig/lkg body weight B.S P and estimation of the percentage remaining in the circulation 45 minutes later ... 

Standard liver function test abnormalities were found in three gout patients who had elevation of serum aspartate amino transferase (Table 3). These also had abnormal B.S.P. retention (more than 5/ at 45 minutes after injection) and a total of I4 of the gout subjects had retention exceeding the normal. 

ALAT = alanine amino transferase, ASAT = aspartate amino transferase, LDH = lactate dehydrogenase, LDL = low-density lipoprotein, VLDL = very low-density lipoprotein, HDL = high-density lipoprotein. 

T. Oka, N. Komori, M. Kuwahata, Y. Hiroi, T. Shimoda, M. Okada, and Y. Natori. Pyridoxal 5 -phosphate modulates expression of cytosolic aspartate amino-transferase gene by inactivation of glucocorticoid receptor. J. Nutr. Sci. Vitaminol. 41 363-375 (1995). 

Aspartate amino-transferase alanine aminotransferase (ASAT/ALAT)... 

Y. Morino and M. Okamoto (1973), Labeling of the active site of cytoplasmic aspartate amino transferase by j -chloro-L-alanine. Biochem. Biophys. Res. Commun. 50, 1061-1067. 

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