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Amino acid sequence of a 32‐residue region around the thiol ester site in duck ovostatin
Author(s) -
Nagase Hideaki,
Brew Keith
Publication year - 1987
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 - 10.1016/0014-5793(87)80196-5
Subject(s) - size exclusion chromatography , chemistry , thiol , sephadex , peptide sequence , trypsin , amino acid , residue (chemistry) , protein primary structure , ion chromatography , biochemistry , chromatography , cyanogen bromide , peptide , enzyme , gene
To obtain the amino acid sequence at the thiol ester site in duck ovostatin for comparisons with other proteins, the native ovostatin was labeled with 14 CH 3 NH 2 at the reactive thiol ester site. The modified protein was reduced, carboxymethylated, and digested with trypsin. 14 C‐labeled peptides isolated by gel filtration with Sephadex G‐50, ion‐exchange chromatography on DEAE‐cellulose and HPLC were subjected to automated sequence analysis, and the stretch of 32 amino acid residues containing the 14 CH 3 NH 2 ‐binding site were determined. A comparison of this sequence with the corresponding sequences in α 2 ‐macroglobulin, and complement components C3 and C4 revealed 72, 31 and 34% homology, respectively. The results indicate that ovostatin is a close relative to plasma α‐macroglobulins and may share a common ancestor with C3 and C4.