[The enzymatic analysis of sphingomyelin in HDL (author's transl)]

A simple method is described for the enzymatic determination of sphingomyelin in the apolipoprotein B-free supernatants prepared by precipitation of blood sera with phosphotungstate/MgCl2. The analysis is based on the enzymatic hydrolysis of sphingomyelin, by sphingomyelinase from B. cereus, into phosphorylcholine and N-acylsphingosine, and subsequent hydrolysis of phosphorylcholine by alkaline phosphatase. The choline formed is determined by choline kinase in an optical test. The results from this method were in good agreement with those obtained by the conventional chemical sphingomyelin determination. Furthermore, there was a good correlation between the sphingomyelin concentrations obtained from the HDL fractions isolated by ultracentrifugation (1.063-1.21 kg/l) and those obtained from the apolipoprotein B free supernatants after phosphotungstate/mgCl2 precipitation of sera.