Creatine kinase isoenzyme variants in human serum.

Area of Science:

• Biochemistry
• Clinical Chemistry
• Enzymology

Background:

• Creatine kinase (CK) is a crucial enzyme in cellular energy homeostasis.
• CK exists in different isoenzyme forms (MM, MB, BB) with distinct tissue distributions.
• Abnormal CK isoenzyme patterns can indicate specific pathologies.

Purpose of the Study:

• To investigate the cause of supranormal creatine kinase B subunit activity in patients with normal total CK.
• To characterize the electrophoretic properties of unusual CK isoenzymes observed in patient serum.
• To explore the potential clinical significance of these findings.

Main Methods:

• Serum samples from approximately 800 patients were analyzed.
• Total creatine kinase and creatine kinase subunit B activities were measured using the Scandinavian method.
• Creatine kinase isoenzymes were separated and analyzed by electrophoresis.
• An M subunit inhibitory antibody was used to differentiate CK isoenzymes.

Main Results:

• Eight patients exhibited elevated creatine kinase B subunit activity with normal or near-normal total CK activity.
• Electrophoresis revealed abnormal migrating CK isoenzyme bands between MM and MB in these patients.
• These abnormal bands are hypothesized to be creatine kinase BB isoenzymes with altered electrophoretic mobility.
• No common underlying disorder was identified in the affected patients.

Conclusions:

• The presence of abnormally migrating CK isoenzymes suggests a potential diagnostic marker.
• Altered electrophoretic mobility of creatine kinase BB may occur independently of specific diseases.
• Further research is needed to elucidate the exact nature and clinical implications of these findings.