EVALUATION OF A NEW RAPID PLASMA LIPASE ASSAY SYSTEM

A rapid, simple, and sensitive method is described for the assay of post-heparin plasma lipase. The incubation system contains only the ingredients required for the assay: plasma, as the source of lipase, lipoprotein, and albumin; fat emulsion as substrate, and Tris buffer, pH 8.1. With a 3-hour incubation period, liberation of fatty acid is proportional to log of either heparin dose or lipase concentration. The lipase assay utilizes a new free fatty acid assay procedure (21) developed in this laboratory. This procedure depends on the formation of a complex soluble in toluene between Rhodamine B, uranyl ion, and the fatty acid anion. The method was used to investigate the effects of pH, 1 m NaCl, and substrate on the assay system. The stability of the enzyme on refrigeration and freezing was also investigated. A need for an international standardized method is mentioned. © 1969.