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Properties and Regional Distribution of Pyruvate Dehydrogenase Kinase in Rat Brain
Author(s) -
Sheu KwanFu Rex,
Lai James C. K.,
Blass John P.
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb09722.x
Subject(s) - pyruvate dehydrogenase kinase , pyruvate dehydrogenase complex , pyruvate dehydrogenase phosphatase , dihydrolipoyl transacetylase , pyruvate decarboxylation , pyruvate carboxylase , pyruvate kinase , pkm2 , biochemistry , oxoglutarate dehydrogenase complex , chemistry , biology , enzyme , glycolysis
A method is described to measure directly in rat brain the activity of pyruvate dehydrogenase kinase (PDH a kinase; EC 2.7.1.99), which catalyzes the inactivation of pyruvate dehydrogenase complex (PDHC, EC 1.2.4.1, EC 2.3.1.12, and EC 1.6.4.3). The activity showed the expected dependence on added ATP and divalent cation, and the expected inhibition by dichloroacetate, pyruvate, and thiamin pyrophosphate. These results, and the properties of pyruvate dehydrogenase phosphate phosphatase (EC 3.1.3.43), indicate that the mechanisms of control of phosphorylation of PDHC seem qualitatively similar in brain to those in other tissues. Regionally, PDH a kinase is more active in cerebral cortex and hippocampus, and less active in hypothalamus, pons and medulla, and olfactory bulbs. Indeed, the PDH a kinase activity in olfactory bulbs is uniquely low, and is more sensitive to inhibition by pyruvate and dichloroacetate than that in the cerebral cortex. Thus, there are significant quantitative differences in the enzymatic apparatus for controlling PDHC activity in different parts of the brain.