Isolation and Primary Structure of Proteinase Inhibitors from Erythrina variegata(LINN.) var. Orientalis Seeds

Yoshiaki Kouzuma, Masanobu Suetake, Makoto Kimura, Nobuyuki Yamasaki

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


The Kunitz-type trypsin inhibitors, ETIa and ETIb, and chymotrypsin inhibitor ECI were isolated from the seeds of Erythrina variegata. The proteins were extracted from a defatted meal of seeds with 10 mM phosphate buffer, pH 7.2, containing 0.15 M NaCl, and purified by DEAE-cellulose and Q-Sepharose column chromatographies. The stoichiometry of trypsin inhibitors with trypsin was estimated to be 1: 1, while that of chymotrypsin inhibitor with chymotrypsin was 1: 2, judging from the titration patterns of their inhibitory activities. The complete amino acids of the two trypsin inhibitors were sequenced by protein chemical methods. The proteins ETIa and ETIb consist of 172 and 176 amino acid residues and have Mr 19, 242 and Mr 19, 783, respectively, and share 112 identical amino acid residues, which is 65% identity. They show structural features characteristic of the Kunitz-type trypsin inhibitor (i.e., identical residues at about 45% with soybean trypsin inhibitor STI). Furthermore, the trypsin inhibitors show a significant homology to the storage proteins, sporamin, in sweet potato and the taste-modifying protein, miraculin, in miracle fruit, having about 30% identical residues.

Original languageEnglish
Pages (from-to)1819-1824
Number of pages6
JournalBioscience, Biotechnology and Biochemistry
Issue number11
Publication statusPublished - 1992

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry


Dive into the research topics of 'Isolation and Primary Structure of Proteinase Inhibitors from Erythrina variegata(LINN.) var. Orientalis Seeds'. Together they form a unique fingerprint.

Cite this