FEBS Letters | |
Removal of substrate inhibition in a lactate dehydrogenase from human muscle by a single residue change | |
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
【 预 览 】
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