Pyruvate dehydrogenase kinase/activator in rat heart mitochondria, Assay, effect of starvation, and effect of protein-synthesis inhibitors of starvation.
Purified pig heart pyruvate dehydrogenase complex is denuded of its intrinsic pyruvate dehydrogenase kinase activity by sedimentation from dilute solution (60 munits/ml). Kinase activity is restored by a supernatant fraction prepared by high-speed centrifugation of rat heart mitochondrial extracts; the factor responsible is referred to as kinase/activator. Kinase/activator was also assayed by its ability to accelerate NgATP-induced inactivation in dilute solutions of unprocessed complex (50 munits/ml). With this assay it has been shown that the activity of kinase/activator in heart mitochondria is increased 3-6 fold by starvation of rats for 48 h. This increase was prevented completely by cycloheximide treatment and prevented partially by puromycin treatment of rats during starvation. The concentration of kinase/activator in heart mitochondria fell during 20 h of re-feeding of 48 h-starved rats; this fall was correlated with an increase in the proportion of complex in the active form. Kinase/activator was also extracted from ox kidney mitochondria, and on gel filtration (Sephadex G-100, superfine grade) was eluted close to the void volume. Kinase/activator (ox kidney or rat heart) was thermolabile, non-diffusable on dialysis, and inactivated by trypsin. The results of this study appear to show increased cytoplasmic synthesis in starvation of pyruvate dehydrogenase kinase and/or of an activator of the kinase.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D005502:Food; D007700:Kinetics; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011691:Puromycin / Q000494:pharmacology; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D051381:Rats; D013217:Starvation / Q000201:enzymology*; D014357:Trypsin / Q000494:pharmacology
D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex; C029131:pyruvate dehydrogenase activator; D011691:Puromycin; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D014357:Trypsin