Author/Editor		Popović, T; Brzin, J; Ritonja, A; Turk, V
Title		Different forms of human cystatin C
Type		članek
Source		Biol Chem Hoppe Seyler
Vol. and No.		Letnik 371, št. 7
Publication year		1990
Volume		str. 575-80
Language		eng
Abstract		Two isoelectric forms of human cystatin C with pI 9.2 and 7.8 have been isolated from urine of patients with different nephrological disorders. Treatment of both forms with alkaline phosphatase revealed that the difference between them is not due to the phosphorylation of some amino-acid residue. Further purification of cystatin C with pI 9.2 by hydrophobic chromatography and N-terminal sequencing showed that it consists predominantly of the full-length form of cystatin C with the N-terminal sequence SSPG-. Cystatin C with pI 7.8 was separated into two peaks. The first represented a pure form truncated by an octapeptide and beginning with the N-terminal sequence LVGG-. The second was a mixture containing 33 percent of the first peak and 66 percent of a truncated form with the N-terminal sequence VGGP-. Inhibitory activity of the full-length cystatin C and the pure truncated form has been measured against cathepsins B, H and L and show no significant differences in Ki values. These results further support the proposed mechanism of interaction of cysteine proteinases with their inhibitors cystatins (Bode, W., Engh, R., Musil, D., Thiele, U., Huber, R., Karshikow, A., Brzin, J., Kos, J. & Turk, V. (1988) EMBO J. 7, 2593-2599).
Descriptors		CATHEPSINS CYSTATINS AMINO ACID SEQUENCE CATHEPSIN B CYSTATINS ISOELECTRIC FOCUSING ISOELECTRIC POINT KIDNEY DISEASES MOLECULAR SEQUENCE DATA URINE