Agarose gel isoelectric focusing of creatine kinase (EC 2.7.3.2) isoenzymes from different human tissue extracts

Abstract

Creatine kinase (EC 2.7.3.2) isoenzymes can be separated into a three-band pattern by means of various electrophoretic techniques [ 1,2]. The cathodic band represents CK-MM, the intermediate band CK-MB and the anodic band CK-BB. Isoelectric focusing, an analytical procedure with a high resolution, often exceeding that obtainable by means of electrophoresis, was applied to the separation of creatine kinase isoenzymes by Karlsson et al [3] and Thorstensson et al [4]. However, the heterogeneity of CK-MM in human serum was demonstrated by Sjovall and Jergil [S] using polyacrylamide gel electrophoresis and was first explicitly stated by Wevers et al [6]. They reported the existence of three CK-MM bands in human sera with a total CK > 500 U/l after agarose gel electrophoresis [6], and postulated two different CK-M subunits [7] forming a CK-M,M,-, an M,M,and an M,M,-band. Chapelle et al [8] could demonstrate five distinguishable CK-MM bands in a myocardium extract after incubation with normal serum by means of polyacrylamide gel isoelectric focusing. Using their technique, Wevers et al [6] only detected a single CK-BB band. We examined creatine kinase from uterine, cortical, muscular and myocardial cytoplasm by means of agarose gel isoelectric focusing.