Publications

• Studies on the substrate and stereo/regioselectivity of adipose triglyceride lipase, hormone-sensitive lipase, and diacylglycerol-O-acyltransferases.

  Eichmann T.O., Kumari M., Haas J.T., Farese R.V. Jr., Zimmermann R., Lass A., Zechner R.

  Adipose triglyceride lipase (ATGL) is rate-limiting for the initial step of triacylglycerol (TAG) hydrolysis, generating diacylglycerol (DAG) and fatty acids. DAG exists in three stereochemical isoforms. Here we show that ATGL exhibits a strong preference for the hydrolysis of long-chain fatty aci ... >> More

  Adipose triglyceride lipase (ATGL) is rate-limiting for the initial step of triacylglycerol (TAG) hydrolysis, generating diacylglycerol (DAG) and fatty acids. DAG exists in three stereochemical isoforms. Here we show that ATGL exhibits a strong preference for the hydrolysis of long-chain fatty acid esters at the sn-2 position of the glycerol backbone. The selectivity of ATGL broadens to the sn-1 position upon stimulation of the enzyme by its co-activator CGI-58. sn-1,3 DAG is the preferred substrate for the consecutive hydrolysis by hormone-sensitive lipase. Interestingly, diacylglycerol-O-acyltransferase 2, present at the endoplasmic reticulum and on lipid droplets, preferentially esterifies sn-1,3 DAG. This suggests that ATGL and diacylglycerol-O-acyltransferase 2 act coordinately in the hydrolysis/re-esterification cycle of TAGs on lipid droplets. Because ATGL preferentially generates sn-1,3 and sn-2,3, it suggests that TAG-derived DAG cannot directly enter phospholipid synthesis or activate protein kinase C without prior isomerization. << Less

  J. Biol. Chem. 287:41446-41457(2012) [PubMed] [EuropePMC]

  This publication is cited by 30 other entries.

• Positional specificity of hormone-sensitive lipase from rat adipose tissue.

  Fredrikson G., Belfrage P.

  Hormone-sensitive lipase, purified from rat adipose tissue (Fredrikson, G., Strålfors, P., Nilsson, N. O., and Belfrage, P. (1981) J. Biol. Chem. 256, 6311-6320), has been incubated with tri-, di-, and monooleoyl[3H]glycerol, and the acylglycerol reaction products were isolated by thin layer chrom ... >> More

  Hormone-sensitive lipase, purified from rat adipose tissue (Fredrikson, G., Strålfors, P., Nilsson, N. O., and Belfrage, P. (1981) J. Biol. Chem. 256, 6311-6320), has been incubated with tri-, di-, and monooleoyl[3H]glycerol, and the acylglycerol reaction products were isolated by thin layer chromatography on silicic acid, impregnated with boric acid. Trioleoylglycerol was hydrolyzed with the intermediate accumulation of monooleoylglycerol, mainly the 2-isomer, and a small amount of 1,2(2,3)-, but no measurable, 1,3-dioleoylglycerol. 2-Monooleoylglycerol was also the major acylglycerol reaction product from 1,2(2,3)-dioleoylglycerol hydrolysis, which occurred at a Vmax of 60% of that with the 1,3-isomer. Part of the 1(3)-monooleoylglycerols found were formed by acyl migration, but 2-ester bond cleavage was directly demonstrated by the use of 1,3-dioleoyl-2-[14C]oleoyl[3H]glycerol as substrate, and by determination of the 14C/3H ratios of the acylglycerol reaction products. Based on the hydrolysis of specific monooleoylglycerol isomers, it was estimated that the 1(3)-ester bonds of the acylglycerols were hydrolyzed 3-to 4-fold faster than the 2-ester bonds. The main lipolytic reaction sequence catalyzed by hormone-sensitive lipase is thus triacylglycerol leads to 1,2(2,3)-diacylglycerol leads to 2-monoacylglycerol. However, the preference for the 1(3)-ester bonds is less marked than that of, e.g. pancreatic and lipoprotein lipase. << Less

  J. Biol. Chem. 258:14253-14256(1983) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.

• Hydrolysis of neutral lipid substrates by rat hepatic lipase.

  Wilcox R.W., Thuren T., Sisson P., Kucera G.L., Waite M.

  Rat hepatic lipase, an enzyme whose involvement in the catabolism of lipoproteins remains poorly defined, has both neutral lipid and phospholipid hydrolyzing activity. We determined the substrate specificity of hepatic lipase for 1-oleoyl-sn-glycerol, 1,2-dioleoyl-sn-glycerol, and 1,3-dioleoyl-sn- ... >> More

  Rat hepatic lipase, an enzyme whose involvement in the catabolism of lipoproteins remains poorly defined, has both neutral lipid and phospholipid hydrolyzing activity. We determined the substrate specificity of hepatic lipase for 1-oleoyl-sn-glycerol, 1,2-dioleoyl-sn-glycerol, and 1,3-dioleoyl-sn-glycerol in the Triton X-100 mixed micellar state, and compared these results to those obtained previously in our laboratory for the phospholipid substrates phosphatidic acid (PA), phosphatidylethanolamine (PE), and phosphatidylcholine (PC). Vmax values were determined by diluting the substrate concentration in the surface of the micelle by Triton X-100. The Vmax values obtained were 144 mumol/min/mg for 1-oleoyl-sn-glycerol, 163 mumol/min/mg for 1,2-dioleoyl-sn-glycerol, and 145 mumol/min/mg for 1,3-dioleoyl-sn-glycerol. These values were higher than those obtained earlier for phospholipids which were 67 mumol/min/mg for PA, 50 mumol/min/mg for PE and 4 mumol/min/mg for PC. In addition, the mole fraction of lipid substrate at half maximal velocity (K) in the surface dilution plot was lower for the neutral lipid substrates as compared to those obtained for the phospholipid substrates. When the hydrolysis of 1,3-dioleoyl-sn-glycerol mixed micelles was studied as a function of time, cleavage at the sn-1 and sn-3 positions occurred at the same rate, suggesting that hepatic lipase is not stereoselective with respect to 1,3-diacyl-sn-glycerol substrates.(ABSTRACT TRUNCATED AT 250 WORDS) << Less

  Lipids 26:283-288(1991) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• In vitro stereoselective hydrolysis of diacylglycerols by hormone-sensitive lipase.

  Rodriguez J.A., Ben Ali Y., Abdelkafi S., Mendoza L.D., Leclaire J., Fotiadu F., Buono G., Carriere F., Abousalham A.

  Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids in adipocytes and shows a substrate preference for the diacylglycerols (DAGs) originating from triacylglycerols. To determine whether HSL shows any stereopreference during the hydrolysis of diacylglycerols, r ... >> More

  Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids in adipocytes and shows a substrate preference for the diacylglycerols (DAGs) originating from triacylglycerols. To determine whether HSL shows any stereopreference during the hydrolysis of diacylglycerols, racemic 1,2(2,3)-sn-diolein was used as a substrate and the enantiomeric excess (ee%) of residual 1,2-sn-diolein over 2,3-sn-diolein was measured as a function of DAG hydrolysis. Enantiomeric DAGs were separated by performing chiral-stationary-phase HPLC after direct derivatization from lipolysis product extracts. The fact that the ee% of 1,2-sn-diolein over 2,3-sn-diolein increased with the level of hydrolysis indicated that HSL has a preference for 2,3-sn-diolein as a substrate and therefore a stereopreference for the sn-3 position of dioleoylglycerol. The ee% of 1,2-sn-diolein reached a maximum value of 36% at 42% hydrolysis. Among the various mammalian lipases tested so far, HSL is the only lipolytic carboxylester hydrolase found to have a pronounced stereospecificity for the sn-3 position of dioleoylglycerol. << Less

  Biochim. Biophys. Acta 1801:77-83(2010) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.