Stability and electrophoretic characteristics of creatine kinase BB extracted from human brain and intestine

Academic Article

Abstract

  • Creatine kinase (CK; EC 2.7.3.2) isoenzyme BB extracted from brains of rats reportedly undergoes modification at 37°C, leaving an electrophoretic variant that accounts for most of the residual CK activity. This variant, called CK-BB', migrates on electrophoresis similarly to creatine kinase isoenzyme MB. Using electrophoresis and immunoinhibition with antiserum to creatine kinase isoenzyme MM, we found CK-BB to be the only identifiable cytoplasmic isoenzyme in surgical samples from human brain and intestine. In contrast, we found that some samples of brain obtained at autopsy contain CK-BB'. We also found that CK-BB extracted from human brain was converted to CK-BB' upon incubation in serum or plasma at 37°C. We found a similar development of CK-BB' in incubation mixtures of serum or plasma containing CK-BB obtained from surgical samples of human intestine. The development of CK-BB' during infarction of the gastrointestinal system may thus be a source of false-positive CK-MB in the laboratory verification of myocardial infarction when electrophoresis is used as the only method to identify CK isoenzymes.
  • Published In

  • Clinical Chemistry  Journal
  • Author List

  • Chastain SL; Ketchum CH; Grizzle WE
  • Start Page

  • 489
  • End Page

  • 492
  • Volume

  • 34
  • Issue

  • 3