An enzyme caught in action: Direct imaging of hydrolytic function and domain formation of phospholipase A2 in phosphatidylcholine monolayers

FEBS Letters

Salesse, C.¹  Grainger, D.W.¹  Reichert, A.¹  Ringsdorf, H.¹ 

[1]Institute für Organische Chemie, J-J Becher Weg 18-20, University of Mainz, D-6500 Mainz, FRG

关键词: Monolayer;    Enzymatic hydrolysis;    Fluorescence microscopy;    Phospholipid;    Phospholipase A2;    Domain;    DPPC;    dipalmitoylphosphatidylcholine;    PLA2;    phospholipase A2;   

DOI  :  10.1016/0014-5793(89)80892-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Phospholipase A₂, a ubiquitous lipolytic enzyme that actively catalyses hydrolysis of phospholipids, has been studied as a model for enzyme-substrate reactions, as a membrane structural probe, and as a model for lipid-protein interactions. Its mechanism of action remains largely controversial. We report here for the first time direct microscopic observation of the lipolytic action of fluorescently marked phospholipase A₂ (Naja naja naja) against phosphatidylcholine monolayers in the lipid phase transition region. Under these conditions, phospholipase A₂ is shown to target and hydrolyse solid-phase lipid domains of L-α-dipalmitoylphosphatidylcholine. In addition, after a critical extent of monolayer hydrolysis, the enzyme itself aggregates into regular, visible proteinaceous domains within the lipid monolayer. Solid-phase lipid hydrolysis indicates a preferential hydrolytic environment for phospholipase A₂ while enzyme domain formation points to a possible allosteric inhibition mechanism by hydrolysis products.

【 授权许可】

Unknown