Aminotransferases promoters

VK Chary, JL de la Fuente, AL Leitao, P Liras, JF Martin. Overexpression of the lat gene in Nocardia lactamdurans from strong heterologous promoters results in very high levels of lysine-6-aminotransferase and up to two-fold increase in cepha-mycin C production. Appl Microbiol Biotechnol 53 282-288, 2000. 

GS in plants is the key enzyme of the GS/GOGAT (glutamine synthetase/g1utamine 2-oxyg1utarate aminotransferase) pathway and thus plays a crucial role in ammonia assimilation/reassimilation (117. 118). GS inhibition by phosphinothricin causes accumulation of toxic levels of ammonia. Since ammonia production is increased by photorespiration and conversion of nitrite to ammonia (also light-dependent), nitrogen fertilizers and light act to promote phosphinothricin efficacy (119). 

The most severe complication of EPP is progressive hepatic failure that is caused by accumulation of protoporphyrin in the liver.About 20% of patients have abnormal biochemical tests of fiver function, particularly increased aspartate aminotransferase, but only 2% to 5% of patients develop fiver failure. EPP may also increase the risk of cholelithiasis, the formation of gallstones being promoted by high concentrations of protoporphyrin in the bile. 

A bacterial aminotransferase [46] promotes a decarboxylative transamination reaction with a-aminoisobutyrate in the presence of pyruvate. The reaction occurs via the sequence of Fig. 12 involving an initial cleavage of the Q-COjH bond in the substrate pyridoxal-P Schiff base complex (Fig. 12, 1) followed by reprotonation at C-4 of the coenzyme to give the pyridoxamine-P-enzyme complex (Fig. 12, 4) that participates in the transamination of pyruvate. However, the enzyme will also transform L-alanine at a significant rate by a half-transamination reaction into pyruvate, thereby implying that it is now the C -H bond of the amino acid that is first broken. 

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