Determination and properties of monoglyceride hydrolase in human post-heparin plasma

Abstract

A simple and reproducible radioactive assay for measurement of monoglyceride hydrolase activity in human post-heparin plasma was developed. The maximal activity was obtained using Triton X-100 in the emulsifiers used for the preparation of substrates. The pH optimum was observed to be between pH 8.5 and 9.5. Zero order kinetics were found within 90 min incubation at 37°. The enzyme activity was inhibited progressively with increasing concentrations of sodium dodecyl sulfate, sodium taurodeoxycholate and sodium deoxycholate, whereas bovine serum albumin in the concentrations used was without effect. 1.0 M sodium chloride and protamine sulfate, effective inhibitors of lipoprotein lipase, slightly activated the post-heparin monoglyceride hydrolase activity. Various lipids in concentrations used were without effect on the enzyme activity. These findings suggested that no types of hyperlipoproteinemia influenced the values obtained with the present method for determination of monoglyceride hydrolase activity in post-heparin plasma.