Peptide B, the N-terminal fragment of thioredoxin obtained by cyanogens bromide treatment was aminoethylated and digested with pepsin. Eight peptides were separated by high voltage paper electrophoresis and chromatography and characterized with respect to amino acid sequence. The results account for all 37 residues peptide B. The N-terminal sequence of peptide B was determined as: Ser-Asp-Lys-Ile-Ile-His-Leu-Thr-Asp-Asp-Ser-Phe. [ABSTRACT FROM AUTHOR]
The isolated α-chain of sea anemone collagen was cleaved at methionyl residues with cyanogen bromide. Eleven unique peptides were isolated by ion-exchange and molecular-sieve chromatography, eight of them in approximately equimolar amounts. Characterization of the eleven peptides with regard to amino-acid composition and molecular weight demonstrated that the isolated peptides account for all of the amino acids and for the molecular weight of the α-chain within experimental error. Since the molecule of sea anemone collagen contains ten methionyl residues, the data of the present paper confirm earlier analytical and preparative results that this invertebrate collagen is made up of three identical α-chains. In comparison with known collagens, on the basis of quantitative and qualitative features of amino-acid compositions, the cyanogen bromide peptides of sea anemone collagen indicate genetical relationship of sea anemone collagen to basement membrane collagen. [ABSTRACT FROM AUTHOR]