Compartmentation of acetyl-coA in rat-liver mitochondria.
The ratio of the specific radioactivities of 3-hydroxybutyrate: citrate was determined in rat liver mitochondria which were incubated in the presence of [1-14C]palmitate, pyruvate, bicarbonate, ATP, phosphate and malonate. Without compartmentation this ratio would maximally be 2, however, under our conditions values of 2.5-3.7 were observed. In further experiments with mitochondria, the sensitivity of pyruvate carboxylase for acetyl-CoA produced from various precursors was tested. It was found that acetyl-CoA produced from L-acetylcarnitine or by oxidation from either pyruvate, octanoate or palmitylcarnitine but not from leucine led to a stimulation of pyruvate carboxylation. These results demonstrate a compartmentation of acetyl-CoA in liver mitochondria. The further finding that different mitochondrial fractions showed varying ratios of specific radioactivities of 3-hydroxybutyrate:citrate indicates that the observed compartmentation may be explained by the existence of different types of mitochondria with varying enzyme patterns and acetyl-CoA pools.
D000090:Acetoacetates / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives / Q000494:pharmacology; D002951:Citrates / Q000378:metabolism; D003065:Coenzyme A / Q000031:analogs & derivatives*; D006885:Hydroxybutyrates / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D008297:Male; D008314:Malonates / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D051381:Rats
D000090:Acetoacetates; D002951:Citrates; D006885:Hydroxybutyrates; D008293:Malates; D008314:Malonates; D010169:Palmitic Acids; D011773:Pyruvates; D000244:Adenosine Diphosphate; D000105:Acetyl Coenzyme A; D000255:Adenosine Triphosphate; D002331:Carnitine; D003065:Coenzyme A