The use of trypsin to confirm the presence of macrocreatine kinase on isoenzyme electrophoresis

Abstract

Background Macrocreatine kinase (MCK) type 1 is a high molecular weight form of CK that is non-pathological. Identification of MCK is beneficial in preventing unnecessary investigations that may follow a persistently elevated CK of unknown origin. Currently, gel filtration chromatography can be used as a confirmatory technique, but it is laborious, time-consuming and expensive. The aim of this work, carried out as part of a larger investigation into the prevalence of MCK, was to determine whether trypsin can be used as an alternative to confirm the presence of MCK on isoenzyme electrophoresis. Methods Five samples found to have bands running in the MCK region on isoenzyme electrophoresis were treated with trypsin. Electrophoresis was carried out using the Helena Biosciences Sas-1 Plus system. These samples were also analysed by the confirmatory technique of gel filtration chromatography. Results Of the five samples treated with trypsin, three were found to be MCK-positive and two MCK-negative. These results correlated with those obtained by the reference method of gel filtration chromatography. Conclusions There appears to be a potential use of trypsin in confirming the presence of MCK following isoenzyme electrophoresis. If these findings were verified, this would provide a less labour-intensive, less time-consuming and more cost-effective confirmatory technique. Further study is required, which needs to be expanded to include a larger number of patients, before this method can be adopted routinely.