Diacylglycerol hydrolysis in rat liver lysosomes.
The matrix of rat liver lysosomes exhibits high hydrolytic activity towards 1,2-diacylglycerol with an optimum at pH 4.0. The lipolytic reaction follows Michaelis-Menten kinetics (apparent Vmax 470 nmol hydrolysed/min per mg protein; apparent Km 71 microM 1,2-dioleoylglycerol). Formation of 1- and 2-monooleoylglycerols indicates an initial attack at both the primary and secondary ester bonds. The lysosomal matrix also catalyses (re)acylation reactions, i.e. the formation of 1,2-diacylglycerol from 2-monoacylglycerol and free fatty acid. However, (re)acylation proceeds at a far lower rate than deacylation of diacylglycerol. Lysosomal diacylglycerol hydrolysis is sensitive towards non-ionic detergents, cationic amphiphilic drugs and the lipase inhibitor RHC 80267.
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D004075:Diglycerides / Q000378:metabolism*; D005966:Glucuronidase / Q000378:metabolism; D005989:Glycerides / Q000378:metabolism*; D006596:Hexosaminidases / Q000378:metabolism; D006868:Hydrolysis; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008247:Lysosomes / Q000201:enzymology*; D051381:Rats; D001619:beta-N-Acetylhexosaminidases
D004075:Diglycerides; D005989:Glycerides; D000135:Acid Phosphatase; D006596:Hexosaminidases; D005966:Glucuronidase; D001619:beta-N-Acetylhexosaminidases