Dietary and Hormonal Effects on Adenosine Triphosphate:Adenosine Monophosphate Phosphotransferase Activity in Rat Liver

摘要: Abstract Adenylate kinase activity was measured in rat tissues by a spectrophotometric procedure which ADP formation from ATP and AMP coupled with pyruvate kinase, phosphoenolpyruvate, lactate dehydrogenase to oxidation of NADH. Activity, at 135 µmoles per min g tissue, extremely high the supernatant fraction liver obtained centrifugation 0.25 m sucrose homogenate 100,000 x much lower mitochondria, 13 units g. No found microsomes or nuclei. Both mitochondrial fractions were nearly as active other nucleoside monophosphates cosubstrates AMP, but less triphosphates than ATP. Apparent Km values for both enzymes 0.3 mm MgATP 0.03 AMP. A 48-hour fast increased enzyme 374 g, this lowered strikingly 24 hours, about 40 feeding glucose diet. The fasting level only slightly fat protein In fed alloxandiabetic rats, fasted normal it insulin treatment levels rats. Activities somewhat adrenalectomized effects not pronounced they remained essentially unaffected dietary hormonal alterations.