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Báo cáo khoa học: Essential roles of lipoyl domains in the activated function and control of pyruvate dehydrogenase kinases and phosphatase isoform 1

Four pyruvate dehydrogenase kinase and two pyruvate dehydrogenase phosphatase isoforms function in adjusting the activation state of the pyruvate dehydrogenase complex (PDC) through determining the fraction of active (non-phosphorylated) pyruvate dehydrogenase component. Necessary adaptations of PDC activity with varying meta-bolic requirements in different tissues and cell types are met by the selective expression and pronounced variation in the inherent functional properties and effector sensitivities of these regulatory enzymes. . | Eur. J. Biochem. 270 1050-1056 2003 FEBS 2003 doi 10.1046 j.1432-1033.2003.03468.x MINIREVIEW Essential roles of lipoyl domains in the activated function and control of pyruvate dehydrogenase kinases and phosphatase isoform 1 Thomas E. Roche Yasuaki Hiromasa Ali Turkan Xiaoming Gong Tao Peng Xiaohua Yan Shane A. Kasten Haiying Bao and Jianchun Dong Department of Biochemistry Kansas State University Manhattan Kansas USA Four pyruvate dehydrogenase kinase and two pyruvate dehydrogenase phosphatase isoforms function in adjusting the activation state of the pyruvate dehydrogenase complex PDC through determining the fraction of active nonphosphorylated pyruvate dehydrogenase component. Necessary adaptations of PDC activity with varying metabolic requirements in different tissues and cell types are met by the selective expression and pronounced variation in the inherent functional properties and effector sensitivities of these regulatory enzymes. This review emphasizes how the foremost changes in the kinase and phosphatase activities issue from the dynamic effector-modified interactions of these regulatory enzymes with the flexibly held outer domains of the core-forming dihydrolipoyl acetyl transferase component. Keywords pyruvate dehydrogenase complex PD kinase PD phosphatase dihydrolipoyl acetyltransferase lipoyl domain. Introduction The mitochondrial pyruvate dehydrogenase complex PDC plays a critical fuel selection role in determining whether glucose-linked substrates are converted to acetyl-CoA 1-4 . When carbohydrate stores are reduced mammalian PDC activity is down-regulated and limits the oxidative utilization of glucose in most non-neural tissues. Extended starvation results in PDC activity being profoundly suppressed in most tissues operation of the same regulatory control severely restricts PDC activity in diabetic animals to thereby impede consumption of abundant glucose. Following the intake of excess dietary carbohydrate activation of PDC in fat .