Clostridium pasteurianum glutamine synthetase mechanism

FEBS Letters

Krishnan, Indira S.¹  Dua, Ramji D.¹ 

[1] Head, Biochemistry Laboratories, Department of Chemistry, III Delhi, Hauz Khas, New Delhi 110 016, India

关键词: Clostridium pasteurianum;    Glutamine synthetase;    Active site;    Tyrosine;    Tetranitromethane;   

DOI  :  10.1016/0014-5793(85)80920-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Preliminary chemical modification studies indicated the presence of tyrosine, carboxyl, arginine, histidine and the absence of serine and sulfhydryl residues at or near the active site of Clostridium pasteurianum glutamine synthetase. The conditions for tyrosine modification with tetranitromethane were optimized. The inactivation kinetics follow pseudo-first-order kinetics with respect to enzyme and second order with respect to modifier per active site. There was no inactivation at pH 6.5 suggesting the absence of thiol oxidation. The synthetase and transferase reactions followed the same pattern of inactivation on enzyme modification and both were equally protected by glutamate plus ATP. Thus tyrosine residues are present at the active site of the enzyme and are essential for both tranferase and synthetase activities.

【 授权许可】

Unknown