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Cathepsin L is capable of truncating cystatin C of 11 N‐terminal amino acids
Author(s) -
Popovič Tatjana,
Cimerman Nina,
Dolenc Iztok,
Ritonja Anka,
Brzin Jože
Publication year - 1999
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/s0014-5793(99)00824-8
Subject(s) - cathepsin h , cystatin , cathepsin o , cathepsin a , chemistry , cathepsin b , biochemistry , cathepsin e , cathepsin l1 , microbiology and biotechnology , cystatin c , cysteine , cathepsin , enzyme , biology , renal function
Cystatin C with the 11 N‐terminal amino acids truncated shows a much lower affinity for cysteine proteinases than the intact inhibitor. Such truncation of cystatin C is recorded after action of glycyl endopeptidase and cathepsin L. Incubation of cystatin C with papain, cathepsin B or cathepsin H led to no changes in the cystatin C molecule. Isoelectric focusing of the cathepsin L and cystatin C mixture showed the formation of two new bands. One of them appeared whether E‐64 or PMSF was added or not, evidently representing a cystatin C/cathepsin L complex. The other band is the truncated cystatin C molecule. N‐terminal sequencing after separation by HPLC showed that cystatin C is cleaved by cathepsin L at the Gly11‐Gly12 bond. The action of cathepsin L on cystatin C may be explained by the cleavage of the scissile bond in an inappropriate complex.