Brain-type creatine kinase also known as CK-BB is a creatine kinase that in humans is encoded by the CKBgene.[5]
Function
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. There, CK-BB forms tightly coupled microcompartments for in situ regeneration of ATP that has been used up. The encoded protein reversibly catalyzes the transfer of "energy-rich" phosphate between ATP and creatine or between phospho-creatine (PCr) and ADP. Its functional entity is a homodimer (CK-BB) in brain and smooth muscle as well as in other tissues and cells such as neuronal cells, retina, kidney, bone, etc. In heart, a heterodimer (CK-MB) shahil consisting of one CK-B brain-type CK subunit and one CK-M muscle-type CK subunit is prominently expressed. The encoded CK-BB and CK-MB proteins are members of the ATP:guanido phosphotransferase protein family.[6]
Ectopic expression
Ectopic expression (CKBE) of the B (brain) type of creatine kinase (CK-BB) in red cells and platelets is a rare, benign anomaly detected during a newborn screening program for Duchenne muscular dystrophy.[7][8]
^Kotz R, Leber H, Ramach W, Arbes H, Wolf A (July 1977). "[Clinical observations on the use of high-dose methotrexate treatment in osteogenic sarcoma (author's transl)]". Wien. Klin. Wochenschr. (in German). 89 (14): 474–9. PMID70889.
^Wienker TF, Ulferts A, Ott J, Bender K, Scheuerbrandt G, Arnold H, Ropers HH (1985). "A dominant mutation causing ectopic expression of the creatine kinase B gene maps on chromosome 14". Cytogenet. Cell Genet. 40: 776. doi:10.1159/000316956.
