MULTIENZYME REFERENCE MATERIAL FROM ESTABLISHED HUMAN CELL-LINES AND HUMAN SOURCES

A multi-enzyme reference material was Prepared from seven enzymes of a sparatate aminotransferase (AST, EC 2.6.1.1), alanine aminotransferase (ALT, EC 2.6.1.2), alkaline phosphatase (ALP, EC 3.1.3.1), lactate de hydrogenase (LD, EC 1.1.1.27), creatine kinase (CK, EC 2.7.2.2), gamma -glutamyltranspeptidase (gamma-GT, EC 2.3.2.2) and amylase (AMY, EC 3. 2.1.1) which were purified from human sources including established hu man cell lines. The enzymatic properties of the material closely resem bled those of human serum. In lyophilized form the preparation was sta ble for at least 200 days when stored at 40 degrees C. Intermethod com parisons of the enzyme activities in 80 clinical specimens were done b y correcting the mean values with calibration constants for different assay methods resulting from use of a human serum, the multi-enzyme re ference and a commercial control serum. The results from the compariso n for the six enzymes of AST, ALT, LD, CK, gamma-GT and AMY in use of the multi-enzyme reference were almost the same as those with use of a human serum as a calibrator, but were not satisfactory for ALP. Even though further search for more reliable material for ALP is required t he multi-enzyme reference material can be used for standardization in clinical chemistry.