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Biochemical characterization of two mutants of human pyruvate dehydrogenase, F205L and T231A of the E1α subunit
Author(s) -
Wu YongGe,
Chen WenYang,
Zhang ZiWei,
Yang GuiZheng,
Li Wei,
Duggleby Ronald G.
Publication year - 2003
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1023/b:boli.0000005628.16515.01
Subject(s) - pyruvate dehydrogenase complex , lactic acidosis , cofactor , mutant , biochemistry , protein subunit , enzyme , biology , mutation , pyruvate dehydrogenase kinase , pyruvate dehydrogenase phosphatase , lactate dehydrogenase , gene
Summary: Mutations in the E1α subunit of the pyruvate dehydrogenase multienzyme complex may result in congenital lactic acidosis, but little is known about the consequences of these mutations at the enzymatic level. Here we characterize two mutants (F205L and T231A) of human pyruvate dehydrogenase in vitro , using the enzyme expressed in Escherichia coli . Wild‐type and mutant proteins were purified successfully and their kinetic parameters were measured. F205L shows impaired binding of the thiamin diphosphate cofactor, which may explain why patients carrying this mutation respond to high‐dose vitamin B 1 therapy. T231A has very low activity and a greatly elevated K m for pyruvate, and this combination of effects would be expected to result in severe lactic acidosis. The results lead to a better understanding of the consequences of these mutations on the functional and structural properties of the enzyme, which may lead to improved therapies for patients carrying these mutations.