Using automated stepwise Edman degradation of suitable overlapping peptides, the complete amino acid sequence of the 268 residue peptida α1-CB7 from calf skin collagen was determined. The preparation and ordering of the chymotryptic, tryptic and thermolytic peptides is described in the preceding paper. As shown previously for other peptides from the helical region of collagen, glycine appears in every third position and proline is present in high amount. Hydroxylation of proline to 4-hydroxyproline and lysine to hydroxylysine only occurred in the Y position of the tripeptide unit Gly-X-Y. Non-random distribution of other amino acids between the X and Y positions was also observed. [ABSTRACT FROM AUTHOR]
Peptide A, the C-terminal cyanogen bromide fragment of thioredoxin, was degraded with chymotrypsin and pepsin. Partial sequences of 12 chymotryptic and 6 peptic peptides and the N-terminal tryptic peptide of trifluoro-acetylated peptide A were determined. The results were used to establish the order of the previously described tryptic peptides of peptide A and lead to the complete amino acid sequence of peptide A. Previous experiments had established the amino acid sequence of peptide B, the N-terminal cyanogen bromide fragment of thioredoxin and the present results thus give the complete amino acid sequence of thioredoxin from Escherichia coli B. The molecule contains 108 residues in a single polypeptide chain with a molecular weight of 11,657 as calculated from the sequence. The functional group of the protein occurs in position 32 to 35 and consists of a disulfide bridge formed by two half-cystine residues separated by a glycine and a proline residue. No metals were found as part of the functional group. [ABSTRACT FROM AUTHOR]