Removal of substrate inhibition in a lactate dehydrogenase from human muscle by a single residue change

FEBS Letters

Sessions, Richard B.¹  Clarke, Anthony R.¹  Moreton, Kathleen M.¹  Eszes, Csilla M.¹  Holbrook, J.John¹ 

[1] Molecular Recognition Centre and Department of Biochemistry, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK

关键词: Lactate dehydrogenase;    Substrate inhibition;    Mutagenesis;    Enzyme kinetics;    Protein modelling;    LDH;    lactate dehydrogenase;    pf;    Plasmodium falciparum;    hM4;    human M4;    Taq;    Thermus aquaticus;    Pfu;    Pyrococcus furiosis;    PCR;    polymerase chain reaction;   

DOI  :  10.1016/S0014-5793(96)01317-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

High concentrations of ketoacid substrates inhibit most natural hydroxyacid dehydrogenases due to the formation of an abortive enzyme-NAD⁺-ketoacid complex. It was postulated that this substrate inhibition could be eliminated from lactate dehydrogenases if the rate of NAD⁺ dissociation could be increased. An analysis of the crystal structure of mammalian LDHs showed that the amide of the nicotinamide cofactor formed a water-bridged hydrogen bond to S163. The LDH of Plasmodium falciparum is not inhibited by its substrate and, uniquely, in this enzyme the serine is replaced by a leucine. In the S163L mutant of human LDH-M₄ pyruvate inhibition is, indeed, abolished and the enzyme retains high activity. However, the major contribution to this effect comes from a weakening of the interaction of pyruvate with the enzyme-coenzyme complex.

【 授权许可】

Unknown