Isoenzyme-specific thermostability of human cytosolic creatine kinase.
Creatine kinase (CK) is a key enzyme involved in intracellular energy homeostasis. The distinct tissue distribution of muscle CK (MMCK) and brain CK (BBCK) implies that they function under conditions facing dissimilar environmental stresses. We found that MMCK and BBCK were significantly different in their stability and reversibility against heat stress. MMCK was more stable than BBCK, and BBCK was only marginally stable and began to inactivate at temperatures just above normal body temperature. The thermal inactivation of MMCK was fully irreversible, whereas that of BBCK was highly reversible at temperatures below 55 degrees C. These differences in stability were proposed to be closely correlated to the isoenzymes' adaptation to the distinct tissue environments.
Gao
Yan-Song
YS
State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
Zhao
Tong-Jin
TJ
Chen
Zhe
Z
Li
Chang
C
Wang
Yin
Y
Yan
Yong-Bin
YB
Zhou
Hai-Meng
HM
D052276:Creatine Kinase, BB Form / Q000737:chemistry*; D052283:Creatine Kinase, MM Form / Q000737:chemistry*; D003600:Cytosol / Q000201:enzymology*; D004795:Enzyme Stability; D006358:Hot Temperature; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry
D007527:Isoenzymes; D052276:Creatine Kinase, BB Form; D052283:Creatine Kinase, MM Form