The changes in activation of intracellular aspartate aminotransferase by pyridoxal 5-phosphate after cell death.
Aspartate aminotransferase activity was measured in plasma, in liver and in heart mitochondrial and cytoplasmic preparations from rats immediately after death and after a post-mortem interval of 15 h. No significant stimulation of activity on addition of pyridoxal 5-phosphate to the assay medium could be demonstrated in any preparations obtained immediately after death. Significant stimulation occurred in both cytoplasmic and mitochondrial preparations of liver and myocardium after a 15-h post-mortem interval, but not in plasma stored for the same period. It appears, therefore, that variations in the intracellular saturation of apoenzyme with coenzyme cannot account for the observed differences in activation of aspartate aminotransferase by pyridoxal 5-phosphate in sera from patients with myocardial infarction and liver disease. Changes in degree of saturation of apoenzyme seem to occur intracellularly after cell death or injury and before release into the circulation.
D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D008099:Liver / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D011180:Postmortem Changes; D011732:Pyridoxal Phosphate / Q000494:pharmacology*; D051381:Rats
D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases