PLA1PLA2

PLA1PLA2 refers to enzymes that exhibit both phospholipase A1 and phospholipase A2 activities, meaning they can hydrolyze the ester bonds at the sn-1 and sn-2 positions of glycerophospholipids. This dual specificity is distinct from enzymes that act exclusively as PLA1 or PLA2 and is not universal among phospholipases. In practice, a single protein with PLA1/PLA2 activity can generate a range of products depending on which bond it cleaves, contributing to diverse lipid metabolites.

Phospholipases A1 and A2 cleave fatty acyl chains from glycerophospholipids, producing different bioactive products. PLA1 activity yields a 2-acyl lysophospholipid and a free fatty acid from the sn-1 position, while PLA2 activity produces a 1-lysophospholipid and a fatty acid from the sn-2 position. When a single enzyme possesses both activities, it has the potential to rapidly remodel membranes or generate multiple lipid mediators, influencing signaling pathways and membrane dynamics.

Distribution and examples vary by organism. Some snake venom phospholipases A2 demonstrate dual activity and are often cited as model systems for PLA1/PLA2 function. In mammals, canonical enzymes are typically characterized as either PLA1 or PLA2, with dual activity reported less frequently and often context-dependent. Structural features that enable dual activity typically involve coordinated substrate-binding and catalytic sites that can orient either acyl chain for hydrolysis.

Biological significance includes roles in membrane remodeling, inflammation, and the production of lipid mediators such as free fatty acids and lysophospholipids. Research on PLA1/PLA2 enzymes aids in understanding lipid signaling, venom pathology, and the development of inhibitors that modulate phospholipase activity for therapeutic purposes.