Author/Editor		Laber, B; Krieglstein, K; Henschen, A; Kos, J; Turk, V; Huber, R; Bode, W
Title		The cysteine proteinase inhibitor chicken cystatin is a phosphoprotein
Type		članek
Source		FEBS Lett
Vol. and No.		Letnik 248, št. 1-2
Publication year		1989
Volume		str. 162-8
Language		eng
Abstract		Peptide maps obtained by reversed-phase HPLC of tryptic digests of isoelectric form 1 (pI = 6.5) and 2 (pI = 5.6) of chicken egg white cystatin revealed that the difference was located only in a single peptide (residues Ser-74-Lys-91). Ser-80 of cystatin 2 was subsequently identified as being modified by phosphorylation. Moreover, alkaline phosphatase treatment of a mixture of native cystatin forms 1 and 2 was shown by ion-exchange chromatography to cause the disappearance of isoelectric form 2 with a concomitant increase in form 1. Thus, the existence of two isoelectric forms of chicken cystatin is due to the phosphorylated form 2 and non-phosphorylated form 1.
Descriptors		CYSTEINE PROTEINASES PHOSPHOPROTEINS PROTEINS AMINO ACID SEQUENCE AMINO ACIDS CHICKENS CHROMATOGRAPHY, HIGH PRESSURE LIQUID HYDROLYSIS ISOELECTRIC FOCUSING MOLECULAR SEQUENCE DATA PEPTIDE MAPPING TRYPSIN