Brain-type creatine kinase also known as CK-BB is a creatine kinase that in humans is encoded by the CKB gene. The protein encoded by this gene, CK-BB, consists of a homodimer of two identical brain-type CK-B subunits. BB-CK is a cytoplasmic enzyme involved in cellular energy homeostasis, with certain fractions of the enzyme being bound to cell membranes, ATPases, and a variety of ATP-requiring enzymes in the cell.http://www.creative-enzymes.com/product/Creatine-Kinase-BB-Fraction-Human-Recombinant_1667.html