Purification and amino acid sequence of kunitz-type protease inhibitor found in the hemocytes of horseshoe crab (Tachypleus tridentatus)

Takanori Nakamura, Toshiaki Hirai, Fuminori Tokunaga, Shun-Ichiro Kawabata, Sadaaki Iwanaga

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A low molecular weight protein protease inhibitor was purified from Japanese horseshoe crab (Tachypleus tridentatus) hemocytes. It consisted of a single polypeptide with a total of 61 amino acid residues. This protease inhibitor inhibited stoichiometrically the amidase activity of trypsin (K1=4.60×10-10 M), and also had inhibitory effects on α-chymotrypsin (K1=5.54×10-9M), elastase (K1=7.20×10-8 M), plasmin, and plasma kallikrein. However, it had no effect on T. tridentatus clotting enzyme and factor C, mammalian blood coagulation factors (activated protein C, factor Xa and α-thrombin), papain, and thermolysin. The complete amino acid sequence of this inhibitor was determined and its sequence was compared with those of bovine pancreatic trypsin inhibitor (BPTI) and other Kunitz-type inhibitors. It was found that the amino acid sequence of this inhibitor has a high homology of 47 and 43% with those of sea anemone inhibitor 5-II and BPTI, respectively. Thus, this protease inhibitor appeared to be one of the typical Kunitz-type protease inhibitors.

Original languageEnglish
Pages (from-to)1297-1306
Number of pages10
JournalJournal of biochemistry
Volume101
Issue number5
DOIs
Publication statusPublished - Jan 1 1987

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

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