Each subunit of calpain (EC 18.104.22.168) is proteolytically modified when the enzymes are exposed to calcium. These cleavages appear to be important for regulating the proteolytic activity and calcium-sensitivity of the proteinases. We have synthesized peptides that correspond to the sites of autoproteolytic modification within the catalytic subunit of each calpain. Polyclonal antisera raised against these peptides are highly specific for the unmodified catalytic subunit of each calpain. The antiserum specific for the N-terminal epitope of milli-calpain was used to demonstrate an inverse relationship between the presence of this N-terminal peptide and casein hydrolysis. The antiserum specific for the N-terminal epitope of micro-calpain was used to demonstrate proteolytic modification of the catalytic subunit of μ-calpain in rat erythrocytes treated with ionomycin and calcium.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular|
|State||Published - May 22 1992|
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology