Monoacylglycerol lipase. Regulation and increased activity during hypoxia and ischemia.
The presence of monoacylglycerol lipase was established in extracts of acetone-dried powders from rat and bovine brains using thioester substrate analogs. At pH 7.4, the apparent Km and Vmax values for 1-S-decanoyl-1-mercapto-2,3-propanediol were 56 microM and 227 nmol/h/mg protein in bovine gray matter. The divalent metal ions Ca2+ and Mg2+ had no effect on enzymic activity, but Zn2+ at 500 microM produced a 50% inhibition of this enzyme. Free fatty acids also caused a marked inhibition of monoacylglycerol lipase activity. Norepinephrine and 5-hydroxytryptamine slightly stimulated the enzymic activity. Hypoxic-hypoxia and 30-s postdecapitation ischemia resulted in a considerable increase in monoacylglycerol lipase activity of rat brain. However, the increased activity of monoacylglycerol lipase returned to normal after 5 min of ischemia. The increased activity of monoacylglycerol lipase during hypoxic-hypoxia and short-time ischemia may be partially responsible for increased levels of free fatty acids during these processes.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002545:Brain Ischemia / Q000201:enzymology*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002417:Cattle; D000242:Cyclic AMP / Q000494:pharmacology; D005260:Female; D002534:Hypoxia, Brain / Q000201:enzymology*; D007700:Kinetics; D008994:Monoacylglycerol Lipases / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology; D013045:Species Specificity
D012701:Serotonin; D000242:Cyclic AMP; D002265:Carboxylic Ester Hydrolases; D008994:Monoacylglycerol Lipases; D000109:Acetylcholine; D009638:Norepinephrine