Premium
A catalytic subunit of calpain possesses full proteolytic activity
Author(s) -
Yoshizawa Toshio,
Sorimachi Hiroyuki,
Tomioka Shigeo,
Ishiura Shoichi,
Suzuki Koichi
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01401-l
Subject(s) - calpain , protein subunit , dimer , biochemistry , specificity factor , protease , enzyme , proteolysis , chemistry , neutral protease , gene , organic chemistry , rna dependent rna polymerase , polymerase
Previous studies on the refolding of calpain, a heterodimer comprising a catalytic 80 kDa subunit and a regulatory 30 kDa subunit, indicate that both subunits are required for the expression of full protease activity. We reexamined the conditions for refolding of calpain and found that under optimized conditions the renatured 80 kDa subunit has full enzyme activity even in the absence of the 30 kDa subunit. The 30 kDa subunit stabilizes the 80 kDa subunit rather than enhancing its activity. The theory that calpain functions as a dimer requires reexamination.