The protein encoded by this gene is a cytoplasmic enzyme involved in cellular energy homeostasis.

The encoded protein reversibly catalyzes the transfer of "energy-rich" phosphate between ATP and creatine and between phospho-creatine and ADP.

Its functional entity is a MM-CK homodimer in striated (sarcomeric) skeletal and cardiac muscle.

In heart, in addition to the MM-CK homodimer, also the heterodimer MB-CK consisting of one muscle (M-CK) and one brain-type (B-CK) subunit is expressed.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.