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Bovine Brain Diacylglycerol Lipase: Substrate Specificity and Activation by Cyclic AMP‐dependent Protein Kinase
Author(s) -
Rosenberger Thad A.,
Farooqui Akhlaq A.,
Horrocks Lloyd A.
Publication year - 2007
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-007-3019-7
Subject(s) - diacylglycerol kinase , monoacylglycerol lipase , chemistry , lipase , diacylglycerol lipase , protein kinase c , substrate (aquarium) , enzyme , biochemistry , protein kinase a , triacylglycerol lipase , diglyceride , chromatography , biology , endocannabinoid system , ecology , receptor
Diacylglycerol lipase (EC 3.1.1.3) was purified from bovine brain microsomes using multiple column chromatographic techniques. The purified enzyme migrates as a single band on SDS‐PAGE and has an apparent molecular weight of 27 kDa. Substrate specificity experiments using mixed molecular species of 1,2‐diacyl ‐sn‐ glycerols indicate that low concentrations of Ca 2+ and Mg 2+ have no direct effect on enzymic activity and 1,2‐diacyl ‐sn‐ glycerols are the preferred substrate over 1,3‐diacyl ‐sn‐ glycerols. The enzyme hydrolyzes stearate in preference to palmitate from the sn ‐1 position of 1,2‐diacyl ‐sn‐ glycerols. 1‐ O ‐Alkyl‐2‐acyl ‐sn‐ glycerols are not a substrate for the purified enzyme. The native enzyme had a V max value of 616 nmol/min mg protein. Phosphorylation by cAMP‐dependent protein kinase resulted in a threefold increase in catalytic throughput ( V max = 1,900 nmol/min mg protein). The substrate specificity and catalytic properties of the bovine brain diacylglycerol lipase suggest that diacylglycerol lipase may regulate protein kinase C activity and 2‐arachidonoyl ‐sn‐ glycerol levels by rapidly altering the intracellular concentration of diacylglycerols.