Amino Acid Sequence of C‐Terminal Fragment of Hog Pepsin

Abstract

The C-terminal fragment of hog pepsin, which had been obtained in the preceding study on the cyanogen bromide hydrolysate of this protein, was subjected to sequential studies. The 37-residue peptide was digested in independent experiments by trypsin, chymotrypsin, and pepsin, and the amino acid sequence of the arising peptides was determined. I n parallel experiments the sequence of seventeen amino acid residues in the N-terminal region of the peptide was established by the Edman degradation technique. The obtained data permit the C-terminal peptide of hog pepsin to be ascribed the amino acid sequence Asp-Val-Pro-Thr-Ser-Ser-Gly-GluLeu-Trp-Ile-Leu-Gly-Asp-Val-Phe-Ile-Arg-Gln-Tyr-Tyr-Thr-Val-Phe-Asp-Arg-Ala-Asn-Asn-LysVal-Gly-Leu-Ala-Pro-Val-Ala. These results extend and partly correct our previous knowledge of this region of the pepsin molecule as recorded in literature. The problem of the tryptophan content of pepsin is briefly discussed.

Amino-Acid Sequence of Porcine Pepsin

“…The fragment containing the carboxyl-terminal 37 residues (residues 291-327) was not completely determined in this laboratory because the sequence of this region was already known (1-4). However, we did obtain from the tryptophan-cleavage of this fragment a decapeptide (residue 291-300) with a sequence identical to that previously reported (4). The placement of the cyanogen bromide fragments in the pepsin molecule was accomplished with the amino-acid sequences near the four methionyl residues.…”

“…They include investigations of the amino-acid sequences at the regions near the carboxyl-terminus (1)(2)(3)(4), the amino-terminus (5, 6), the three disulfide bonds (7), the tryptophanyl residues (8,9), the phosphoseryl residue (7,10), two separate active-site aspartyl residues (11,12), and a number of small peptides (13,14). We have confirmed most of these previous findings and now present the complete amino-acid sequence of this enzyme.…”

Characterization and arrangement of tryptic fragments from N‐terminal region of hog pepsin

“…The therrnolysin peptides were isolated by paper chromatography and electrophoresis. These techniques and also the methods of characterization of peptides have been described elsewhere [2] as well as the technique of Edman degradation used [ 11 ]. lStTY~lie 2ndcycte 3 rd cycle Z, th cycte…”

Porcine Luteinizing Hormone and its Subunits

“…The phenylthiohydantoins obtained after each degradation step were analyzed as described above [14].…”

“…Anhydrous hydrazine was prepared from hydrazine hydrate (Fluka, purum) as described elsewhere [12]. N-terminal amino acids were identified as their phenylthiohydantoin derivatives after stepwise degradation [13] by thin layer chromatography on Silufol sheets [14].…”