Diethyl-p-nitrophenyl phosphate: an active site titrant for lipoprotein lipase.
Diethyl-p-nitrophenyl phosphate is an active site-directed irreversible inhibitor of bovine milk lipoprotein lipase catalyzed hydrolysis of the water-soluble substrate, p-nitrophenyl butyrate. Interaction of lipoprotein lipase and the inhibitor in the absence of substrate gives a biphasic kinetics profile, which is consistent with rapid formation of a phosphoryl-lipoprotein lipase intermediate which hydrolyzes slowly. The magnitude of the absorbance increase accompanying formation of the intermediate provides an analytical method for determining lipoprotein lipase active site concentration.
D000818:Animals; D001665:Binding Sites; D002087:Butyrates; D002384:Catalysis; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D008071:Lipoprotein Lipase; D008892:Milk / Q000201:enzymology; D010261:Paraoxon; D010654:Phenylbutyrates; D010766:Phosphorylation; D012995:Solubility; D013379:Substrate Specificity
D002087:Butyrates; D010654:Phenylbutyrates; C033592:4-nitrophenyl butyrate; D008071:Lipoprotein Lipase; D010261:Paraoxon