Biochemical characterization of two mutants of human pyruvate dehydrogenase, F205L and T231A of the E1α subunit

Author: Wu Yong-Ge   Chen Wen-Yang   Zhang Zi-Wei   Yang Gui-Zheng   Li Wei   Duggleby Ronald G.   Duggleby Ronald G.  

Publisher: Springer Publishing Company

ISSN: 0141-8955

Source: Journal of Inherited Metabolic Disease, Vol.26, Iss.7, 2003-01, pp. : 671-674

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

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 B1 therapy. T231A has very low activity and a greatly elevated Km 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.

Related content