Liberation of Free Aldehyde from 1-(1-Alkenyl)-sn-glycero-3-phosphoethanolamine (Lysoplasmalogen) by Rat Liver Microsomes

Abstract

An enzyme was found in the microsomal fraction of 21 day old-rat liver, which liberates a free aldehyde from 1-(1-alkenyl)-sn-glycero-3-phosphoethanolamine (lysoplasmalogen) and which has an activity of about 42 mU/mg protein under the conditions described. Kinetic data are presented. The pH optimum is found around pH 7.1. SH-blocking reagents, as well as deoxycholate, act as strong inhibitors, while Mg2+ and Ca2+ also inhibit the reaction to some extent. The enzymic activity is specific with respect to the monoradylphospholipid, since the acylated compound 2-acyl-1-(1-alkenyl)-sn-glycero-3-phosphoethanolamine does not serve as substrate. The ether linkage of 1-alkyl-sn-glycero-3-phosphoethanolamine is not hydrolyzed either under these conditions. A similar enzyme activity in liver has only been described for choline-containing lysoplasmalogen.