Author/Editor		Popovič, Tatjana; Cimerman, Nina; Dolenc, Iztok; Ritonja, Anka; Brzin, Jože
Title		Cathepsin L is capable of truncating cystatin C of 11 N-terminal amino acids
Type		članek
Source		FEBS Lett
Vol. and No.		Letnik 455
Publication year		1999
Volume		str. 92-6
Language		eng
Abstract		Abstract 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-GIy12 bond. The action of cathepsin L on cystatin C may be explained by the cleavage of the scissile bond in an inappropriate complex.
Descriptors		CATHEPSINS CYSTATINS CYSTEINE PROTEINASE INHIBITORS AMINO ACID SEQUENCE CHROMATOGRAPHY, HIGH PRESSURE LIQUID RECOMBINANT PROTEINS ELECTROPHORESIS, POLYACRYLAMIDE GEL ISOELECTRIC FOCUSING