Rapid Separation of Plasma Creatine Kinase Isoenzymes by Batch Adsorption on Glass Beads

To separate the MM and MB creatine kinase (EC 2.7.3.2) isoenzymes in small plasma samples, we developed a simple, rapid ion-exchange batch-adsorption procedure with "DEAE Glycophase" glass beads (Corning). All separative steps are performed in a single test tube and can be completed within a few minutes. Results of measurements of isoenzymes in plasma samples from patients with acute myocardial infarction were compared to those obtained with an independent quantitative assay method previously reported. Additional measurements were performed on standard plasma samples containing mixtures of MM and MB isoenzyme purified from human myocardium. Results by the two independent assay procedures agreed well, as did measured isoenzyme activities and activities predicted from the amounts of isoenzyme added. Activities in the fractions containing separated isoenzymes were measured by a direct kinetic fluorometric assay. MB activities in normal plasma averaged 1.6 plus and minus 0.28 U/liter (mean plus and minus SD).