Binding of thiamin thiazolone pyrophosphate to mammalian pyruvate dehydrogenase and its effects of kinase and phosphatase activities. |
| |
Authors: | J R Butler R H Pettit P F Davis L J Reed |
| |
Institution: | Clayton Foundation Biochemical Institute and the Department of Chemistry The University of Texas at Austin, Austin, Texas 78712 USA |
| |
Abstract: | The pyruvate dehydrogenase component of the bovine kidney pyruvate dehydrogenase complex has two thiamin-PP binding sites per α2β2 tetramer. Titration of these binding sites with the transition state analog, thiamin thiazolone pyrophosphate, strongly inhibits phosphorylation of pyruvate dehydrogenase by pyruvate dehydrogenase kinase and ATP. The analog has little effect, if any, on dephosphorylation of phosphorylated pyruvate dehydrogenase by pyruvate dehydrogenase phosphatase. Phosphorylation of pyruvate dehydrogenase inactivates the enzyme, but does not significantly affect the thiamin-PP binding sites. It appears that phosphorylation produces a conformational change in pyruvate dehydrogenase that displaces a catalytic group (or groups) at the active center. |
| |
Keywords: | active nonphosphorylated form of pyruvate dehydrogenase inactive phosphorylated form TTPP thiamin thiazolone pyrophosphate |
本文献已被 ScienceDirect 等数据库收录! |