Open AccessThioredoxin: 4. Amino Acid Sequence of Peptide B
Author(s) -
Holmgren A.
Publication year - 1968
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1968.tb00378.x
Subject(s) - cyanogen bromide , peptide , thioredoxin , peptide sequence , chemistry , biochemistry , chymotrypsin , amino acid , trypsin , enzyme , gene
Tryptic and chymotryptic digestion of peptide B, the N‐terminal fragment obtained by cyanogen bromide cleavage of thioredoxin, provided the information required to determine the contiguity of the peptic fragments studied previously. The complete sequence of the 37 residues of peptide B could thus be established. Peptide B contains the active center of thioredoxin. Its amino acid sequence was found to be: . This sequence supports earlier conclusions drawn from fluorescence studies of thioredoxin, which indicated a close relationship between one or both tryptophan residues and the disulfide bridge of the active site. Peptide maps of the tryptic digests of carboxymethylated thioredoxin and of the two cyanogen bromide fragments are described. Amide nitrogen analyses of thioredoxin and the two cyanogen bromide fragments demonstrate that all seven amide groups of thioredoxin are localized in the C‐terminal fragment (peptide A).