Human glucose‐6‐phosphate dehydrogenase Lysine 205 is dispensable for substrate binding but essential for catalysis

FEBS Letters

Luzzatto, Lucio¹  Mason, Philip J.¹  Bautista, JoséM.¹ 

[1] Department of Haematology, Royal Postgraduate Medical School, University of London, London W12 0NN, UK

关键词: Glucose-6-phosphate dehydrogenase;    Mutagenesis;    Enzymatic catalysis;   

DOI  :  10.1016/0014-5793(95)00474-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

By site-directed mutagenesis of the cloned human glucose-6-phosphate dehydrogenase cDNA, lysine 205 (the residue that after reacting with pyridoxal-5′-phosphate renders inactive enzyme) was mutated to threonine (K205T) to remove the amino group, or to arginine (K205R) to displace the position of the amino group, in order to analyze the role of its nucleophilic group in position ϵ. Compared to the wild-type enzyme, the K205T and K205R mutants retain a specific activity of 2.6 and 11.4%, respectively; their catalytic specificity (K _cat/K _m) is drastically decreased, whereas the K _m values for both substrates are only slightly increased. These findings in the light of the 3D structure of G6PD suggest that the ϵ-amino group of lysine 205 can favour a hydrogen bond within the active pocket essential for catalysis.

【 授权许可】

Unknown