Acid lipase activity of human lymphocytes.
Acid lipase activity was examined in human leukocytes using 4-methylumbelliferyl esters in a fluorimetric assay. Mononuclear leukocytes had 10--15 times the acid lipase activity of polymorphonuclear leukocytes. The enzyme activity was highest using the oleate ester of 4-methylumbelliferone at pH 4.0, in the presence of L-alpha-phosphatidylcholine and taurodeoxycholic acid (sodium salt). Acid lipase activity was inhibited by diethylaminoethoxyhexestrol, sodium chloride and fluoride, potassium chloride, calcium chloride and albumin, but was unaffected by diethyl p-nitrophenyl phosphate or sulphydryl reagents. There were at least two forms of acid lipase activity: one (A form) was sensitive to heart inactivation (56 degrees C) and corresponded to the enzyme deficient in patients with Wolman's disease; the other (B form) was resistant to heat inactivation and corresponded to the residual enzyme activity found in Wolman's disease.
D001647:Bile Acids and Salts / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008049:Lipase / Q000097:blood*; D008214:Lymphocytes / Q000201:enzymology*; D009000:Monocytes / Q000201:enzymology; D009504:Neutrophils / Q000201:enzymology; D010713:Phosphatidylcholines / Q000494:pharmacology; D013379:Substrate Specificity
D001647:Bile Acids and Salts; D010713:Phosphatidylcholines; D008049:Lipase