On the individuality of aliphatic and alicyclic monoester lipases in human adipose tissue.
Aliphatic and alicyclic monoester lipase activities from human adipose tissue have been comparatively investigated by using [3H] oleoylethanol and [14C] oleoylcholesterol, respectively, as substrates. A number of specific properties proved to be different for each activity. Different rates of decay of hydrolytic activity towards each substrate were observed during heat denaturation. Stability upon exposure to the cold was different for both activities, and the protective effect of glycerol was less effective for oleoylcholesterol than for oleoylethanol lipase. Serial (NH4)2SO4 fractionation in 5% increments showed that the two activities did not precipitate at identical saturation values. The behaviours of the two activities were compared in an affinity system where monoolein, a substrate molecule, served as a ligand for the enzyme(s) in a covalent complex with CH-Sepharose. During chromatography, both activities followed a comparable adsorption-elution pattern, but the oleoylcholesterol to oleoylethanol lipase activity ratio decreased by a factor of 4. Taken together, these data, along with a differential susceptibility to various surfactants, confirm our earlier hypothesis (Arnaud, J. and Boyer, J (1974) Biochim. Biophys. Acta 337, 165--168) that aliphatic and alicyclic monoester lipase activities in human fat are referable to distinct catalytic proteins.
D000273:Adipose Tissue / Q000201:enzymology*; D002788:Cholesterol Esters; D002846:Chromatography, Affinity; D006801:Humans; D007700:Kinetics; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D009829:Oleic Acids; D013329:Structure-Activity Relationship
D002788:Cholesterol Esters; D009829:Oleic Acids; D008049:Lipase