Immobilized anhydrotrypsin as a biospecific affinity adsorbent for the peptides produced by trypsin-like proteases.

Various naturally occurring peptides containing l-arginine at the carboxyl termini were tightly adsorbed at pH 5 on anhydrotrypsin, a chemical derivative of bovine trypsin, immobilized on Sepharose, and desorbed by washing with 5 mm HCl. The largest of the peptides examined was Fragment 2 (“histidine-rich peptide”) with 41 amino acid residues, which had been released from bovine high-molecular-weight kininogen by plasma kallikrein. When only the carboxyl-terminal arginine was removed by carboxypeptidase B, the peptides lost their specific affinity toward the immobilized anhydrotrypsin. The peptide fragments in the tryptic digests of reduced and S-carboxymethylated erabutoxin a were also fractionated effectively by chromatography on this affinity adsorbent. The fragments containing l-lysine at the carboxyl termini showed weaker affinity for the adsorbent than those containing l-arginine at the termini.