Spin-label assay for phospholipase A2.

C S Lai; J Z Zhang; J Joseph

doi:10.1016/0003-2697(88)90461-7

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Spin-label assay for phospholipase A2.

C S Lai·J Z Zhang·J Joseph

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Abstract

A rapid and continuous method for measuring phospholipase A2 activity using electron spin resonance spectroscopy and a spin-labeled phospholipid as a substrate has been developed. The substrate, 1-palmitoyl-2-(4-doxylpentanoyl)glycerophosphocholine, gives rise principally to a broad ESR line in aqueous solution due to strong spin-spin interactions, probably resulting from its micellar formation. Upon addition of bee venom phospholipase A2, the water-soluble product, 4-doxylpentanoic acid, is released which brings about a sharp three-line spectrum. Thus, the kinetics of phospholipase A2 activity can be followed by monitoring the increase in the ESR signal amplitude of the three-line spectrum, which is linearly proportional to the amount of 4-doxylpentanoic acid produced; no separation of the product from the substrate is needed during the measurement. The rate of hydrolysis of 1 nmol min-1 can be accurately measured within a 5-min period of time in a sample volume of 100 microliters. This new method should be useful for assaying phospholipase A2 activities in various biological systems.

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Bee Venoms Electron Spin Resonance Spectroscopy Hydrolysis Lysophospholipids Phospholipases Phospholipases A Phospholipases A2 Phospholipids Journal Article Research Support, U.S. Gov't, P.H.S.

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C S Lai, J Z Zhang, J Joseph. 1988-08-01. Spin-label assay for phospholipase A2.. https://doi.org/10.1016/0003-2697(88)90461-7

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