Activation by calcium of AMP deaminase from the human red cell

FEBS Letters

Almaraz, Laura¹  García-Sancho, Javier¹ 

[1] Departamento de Bioquímica y Biología Molecular y Fisiologia, Facultad de Medicina, Universidad de Valladolid, 47005 Valladolid, Spain

关键词: AMP deaminase;    Ca2+ dependence;    Nucleotide metabolism;    (Red cell);   

DOI  :  10.1016/0014-5793(89)80575-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have investigated the effects of Ca²⁺ on AMP deaminase from human red cells. At variance with the other known modulators, Ca²⁺ increased the apparent affinity for AMP without modifying the characteristic positive cooperativity of the enzyme towards the substrate. Ca²⁺ sensitivity was not modified by dialysis, but dilution of the haemolysate produced an activation of the enzyme similar to that induced by Ca²⁺. Simultaneously, the Ca²⁺ dependence was lost. The sensitivity to other modulators, such as ATP, diphosphoglycerate or phosphate, was not modified by dilution. Partial purification of the enzyme produced the same effects as haemolysate dilution. These results may be interpreted to mean that Ca²⁺ acts by antagonizing an endogenous inhibitor present in red cell lysates.

【 授权许可】

Unknown