The import of carbamoyl-phosphate synthase into mitochondria from foetal rat liver.
A putative precursor of carbamoyl-phosphate synthase was isolated from a microsomal wash fraction and purified by high-pressure liquid chromatography. Autolytic degradation and limited proteolysis were used to characterize the putative precursor of carbamoyl-phosphate synthase and to show its similarity to the processed enzyme. The carbamoyl-phosphate synthase precursor underwent a time-dependent and concentration-dependent conversion into a dimeric or polymeric form. When labelled with 125I and incubated with foetal rat liver mitochondria the precursor was bound to the mitochondria and about 30% of the label was imported into the matrix space. This labelling required the presence of ATP and was time-dependent. Mitoplasts also imported the carbamoyl-phosphate synthase precursor. After import of the precursor, increases in carbamoyl-phosphate synthase activity could be demonstrated in foetal rat liver mitochondria.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000302:isolation & purification*; D005333:Fetus; D008025:Ligases / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D004792:Enzyme Precursors; D000255:Adenosine Triphosphate; D008025:Ligases; D002222:Carbamoyl-Phosphate Synthase (Ammonia)