A model for the molecular mechanism of interfacial activation of phospholipase A2 supporting the substrate theory

FEBS Letters

Thuren, Tom¹ 

[1] Department of Medical Chemistry, University of Helsinki, Siltavuorenpenger 10, SF-00170 Helsinki 17, Finland

关键词: Phospholipase A2;    Pyrene phospholipid;    Mixed micelle;    Cholate;    Enzyme activation;    PLA2;    phospholipase A2;    diPBPC;    1;    2-di[6-(pyren-1-yl)butanoyl]-sn-glycero-3-phosphocholine;    PBPHPC;    1-[6-(pyren-1-yl)butanoyl]-2-[6-(pyren-1-yl)-hexanoyl]-sn -glycero-3-phosphocholine;    I e;    intensity of pyrene excimer fluorescence emission;    I m;    intensity of pyrene monomer fluorescence emission;    CMC;    critical micellar concentration;   

DOI  :  10.1016/0014-5793(88)80805-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Changes occurring in the activity of porcine pancreatic phospholipase A₂ upon formation of mixed micelles of sodium cholate and the fluorescent phosphocholines 1,2-di [6-(pyren-1-yl)butanoyl]-sn-glycero-3-phosphocholine or 1-[6-(pyren-1-yl)butanoyl]-2-[6-(pyren-1-yl)hexanoyl]-sn -glycero-3-phosphocholine were studied. A 2-fold enhancement was observed in the activity of phospholipase A₂ towards both pyrene phospholipids upon exceeding the critical micellar concentration of the system. Changes in the pyrene excimer/monomer fluorescence emission intensity ratio coincide with the enhancement of phospholipase A₂ activity at the critical micellar concentration. Due to the different effects of micellization on the alignment of the pyrene in the two fluorescent probes conformational changes could be assessed. A model describing possible conformations of these pyrene phospholipid molecules below and above the critical micellar concentration is presented and correlated with the interfacial activation of phospholipase A₂.

【 授权许可】

Unknown