TY - JOUR
T1 - The hydrolysis of triacylglycerol and diacylglycerol by a rat brain microsomal lipase with an acidic pH optimum
AU - Cabot, Myles C.
AU - Gatt, Shimon
N1 - Funding Information:
linkages that can be orientated for hydrolysis with similar ease.D ifferent affinities of the enzyme for the substratesm ay also be due to the 1,3-isomer being somewhat less polar. However, synaptosomal lipases have been reported to hydrolyze 1,2(2,3)-and 1,3-diacylglycerols at equal rates [9]. In contrast with pancreatic lipase, lipases from various rat organs have been shown to cleave partial glycerides more rapidly than the triacyl species [lo]. This phenomenon is borne out in the present study and by various studies of lipase in both adipose tissue [ll, 121 and liver [13, 141. The recent finding of a lipase-esterasea ctivity in white matter with an acidic pH optimum is of interest [ 151. This activity hydrolyzing 4-methylumbelliferyl oleate was stimulated by Triton X-100. In the present work, use of natural substrates makes a comparison of these enzyme activities difficult; however, their possible role in maintaining low levels of acylglycerols in neural tissue may be of critical importance. The relatively low amount of neutral glycerolipids in neural tissue as compared to other tissue [ 161 may be due to the presence of an active system in brain which degradesn eutral lipid. This work was supported in part by the National Institutes of Health (Grant NS02967) (S.G.), and is part of a Ph.D. thesis (M.C.C.) submitted to the Hebrew University, Jerusalem.
PY - 1978/9/28
Y1 - 1978/9/28
N2 - Lipase activity towards triacylglycerol and diacylglycerol was measured at pH 4.8 using a microsomal preparation from rat brain as the enzyme source. The optimal pH for the hydrolysis of triacylglycerol was 4.8, with only minor lipolytic activity in the alkaline pH range. Diacylglycerol was the major product of triacylglycerol hydrolysis, with only little monoacylglycerol being formed. When diacylglycerol was the starting substrate it was hydrolyzed at a rate 10-fold greater than triacylglycerol, and the product was monoacylglycerol. The enzyme showed positional specificity for the fatty acid moieties located at the primary positions of sn-glycerol. 1,3-Diacylglycerol was hydrolyzed at greater than twice the rate of the corresponding 1,2(2,3)-isomer.
AB - Lipase activity towards triacylglycerol and diacylglycerol was measured at pH 4.8 using a microsomal preparation from rat brain as the enzyme source. The optimal pH for the hydrolysis of triacylglycerol was 4.8, with only minor lipolytic activity in the alkaline pH range. Diacylglycerol was the major product of triacylglycerol hydrolysis, with only little monoacylglycerol being formed. When diacylglycerol was the starting substrate it was hydrolyzed at a rate 10-fold greater than triacylglycerol, and the product was monoacylglycerol. The enzyme showed positional specificity for the fatty acid moieties located at the primary positions of sn-glycerol. 1,3-Diacylglycerol was hydrolyzed at greater than twice the rate of the corresponding 1,2(2,3)-isomer.
UR - http://www.scopus.com/inward/record.url?scp=0018091694&partnerID=8YFLogxK
U2 - 10.1016/0005-2760(78)90170-4
DO - 10.1016/0005-2760(78)90170-4
M3 - Article
C2 - 29667
AN - SCOPUS:0018091694
SN - 0005-2760
VL - 530
SP - 508
EP - 512
JO - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
JF - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
IS - 3
ER -