Search PubMed⌕ Search

Biomedical subjects

J W Porter

Publications and source records attributed to J W Porter.

At least 55 records · Page 3Linked to original sources
PubMed1980

A new mechanism of regulation of rat liver acetyl-CoA carboxylase activity.

A factor has been found in rat liver supernatant solution which inhibits acetyl-CoA carboxylase activity regardless of the presence or absence of Mg2+ and ATP. Inactivation of the enzyme has been demonstrated via radiochemical and spectrophotometric assay procedures. The inactivation of acetyl-CoA carboxylase is not attributable to either malonyl-CoA decarboxylase activity, to phosphorylation of the enzyme, or to action on substrates or cofactors of the reaction. The activity of the inhibitor is destroyed by heating to 70-80 degrees C for 5 min or by treatment with trypsin. Dialyzing the inhibitor for 24 h at 4 degrees C does not alter its activity in inhibiting acetyl-CoA carboxylase. Hence, it appears that the inhibitor is a regulatory protein that acts directly on acetyl-CoA carboxylase.

Acetyl-CoA Carboxylase↗
PubMed1979

De novo fatty acid synthesis and fatty acid elongation catalyzed by subcellular fractions from hog and human aorta.

De novo synthesis and mitochondrial elongation of fatty acids have been demonstrated in subcellular fractions from hog and human aorta. Microsomal fatty acid elongation has been shown in hog aorta. The activity catalyzing the formation of fatty acids from acetyl and malonyl CoA was associated with a high molecular weight complex in the 6 x 10(6) g x min supernatant fraction. The principal product was palmitic acid. Some myristic and stearic acids were also formed. One elongation system was associated with protein which sedimented between 4500 g x min and 150,000 g x min. It used acetyl CoA but not malonyl CoA, and NADH was the preferred reducing agent. Radioactivity from acetyl CoA was incorporated into many fatty acids. In hog aorta a second elongation system was found associated with protein which sedimented at 6 x 10(6) g x min. It used malonyl CoA preferentially as substrate and either NADH or NADPH as reducing agent.

Acetyl Coenzyme A↗
PubMed1978

Translation and characterization of the fatty acid synthetase messenger RNA.

Fatty acid synthetase messenger RNA was obtained from rat liver polysomal RNA and then injected into Xenopus laevis oocytes. The radioactive fatty acid synthetase protein synthesized in the oocytes was identified by immunoprecipitation with anti-fatty acid synthetase antibody and the immunoprecipitate was then characterized by electrophoresis on sodium dodecyl sulfate-polyacrylamide gel. Co-migration of authentic fatty acid synthetase and the labeled product synthesized in oocytes was observed. Based on sucrose density gradient analysis, the rat liver fatty acid synthetase mRNA has a sedimentation coefficient of approximately 33 S, which agrees with the predicted minimum size necessary to code for the fatty acid synthetase protein. In addition, this mRNA was partially purified with oligo(dT)-cellulose, which indicates that it has a polyadenylate region. The relative in vivo rate of synthesis of fatty acid synthetase and the level of fatty acid synthetase mRNA in liver were also determined during the course of dietary induction of this enzyme. The results indicate that the dietary-induced increase in the level of fatty acid synthetase is probably due to an increased level of the fatty acid synthetase mRNA.

Animals↗