Inhibition of aspartate aminotransferase by glycation in vitro under various conditions.
Incubation of 50 mM D-glucose with aspartate aminotransferase (AST, EC 2.6.1.1) preparations (purified pig heart enzyme or a rat liver 20,000 x g supernatant) at 25 degrees C had no effect on enzyme activity. 50 mM D-fructose or D-ribose gradually inhibited pig heart AST under the same conditions to zero activity after 14 days. 50 mM DL-glyceraldehyde decreased enzyme activity to zero after 6 days of incubation. The inhibition of pig heart AST by 50 mM D-fructose or D-ribose was marked even at a temperature of 4 degrees C but it was less pronounced than at 25 degrees C. There was no effect of 0.5 mM 2-oxoglutarate on AST activity during incubation, while the presence of 25 mM L-aspartate decreased it rapidly. 0.5 mM 2-oxoglutarate partly prevented inhibition of AST by D-ribose or D-fructose, while an analogous experiment with 25 mM aspartate resulted in a rapid decline similar to that in the absence of sugars.
D000818:Animals; D001219:Aspartate Aminotransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D001224:Aspartic Acid / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005632:Fructose / Q000378:metabolism / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005985:Glyceraldehyde / Q000378:metabolism / Q000494:pharmacology; D006031:Glycosylation; D007656:Ketoglutaric Acids / Q000494:pharmacology; D051381:Rats; D012266:Ribose / Q000378:metabolism / Q000494:pharmacology; D013552:Swine; D013696:Temperature
D002241:Carbohydrates; D004791:Enzyme Inhibitors; D007656:Ketoglutaric Acids; D005632:Fructose; D001224:Aspartic Acid; D005985:Glyceraldehyde; D012266:Ribose; D001219:Aspartate Aminotransferases; D005947:Glucose