title: Studies on trypsin inhibitors. Part IX. Synthesis and trypsin inhibitory activity of the duopentacontapeptide corresponding to the amino acid sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal).
abstract: The synthesis of the protected duopentacontapeptide corresponding to the entire amino acid sequence I-52 of porcine pancreatic secretory trypsin inhibitor II (Kazal type) is described. The benzyloxycarbonyltetradecapeptide tert-butyloxycarbonylhydrazide (sequence 1-14) was selectively deblocked with trifluoroacetic acid and used to acylate, by the azide procedure, the peptide free base corresponding to the sequence 15-52. The isolated material was purified by ion exchange chromatography and the protecting groups were removed by successive treatments with anhydrous hydrogen fluoride, 1 M piperidine and mercuric acetate. F02M phosphate buffer, pH8. Determination of the inhibitory capacity indicated that the synthetic material is about 50% effective, at 30:1 inhibitor:trypsin molar ratio in inhibiting the tryptic hydrolysis of Nalpha-benzoyl-DL-arginine-4-nitroanilide. Full inhibition was achieved at a higher inhibitor:trypsin molar ratio. The stability constants and the standard free energy of binding of the complex between trypsin and the synthetic inhibitor have been determined.
mesh_terms: D000595:Amino Acid Sequence; D000813:Anilides / Q000378:metabolism; D000818:Animals; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010084:Oxidation-Reduction; D010446:Peptide Fragments; D010455:Peptides / Q000138:chemical synthesis* / Q000494:pharmacology; D013552:Swine; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000138:chemical synthesis* / Q000494:pharmacology; D014361:Trypsin Inhibitors / Q000138:chemical synthesis*
chemical_list: D000813:Anilides; D010446:Peptide Fragments; D010455:Peptides; D014361:Trypsin Inhibitors; D014359:Trypsin Inhibitor, Kazal Pancreatic