Purification, inhibitory properties, amino acid sequence and identification of the reactive site of a new serine proteinase inhibitor from oil-rape (Brassica napus) seed

FEBS Lett. 1994 Apr 4;342(2):221-4. doi: 10.1016/0014-5793(94)80505-9.

Abstract

A new serine proteinase inhibitor, rapeseed trypsin inhibitor (RTI), has been isolated from rapeseed (Brassica napus var. oleifera) seed. The protein inhibits the catalytic activity of bovine beta-trypsin and bovine alpha-chymotrypsin with apparent dissociation constants of 3.0 x 10(-10) M and 4.1 x 10(-7) M, at pH 8.0 and 21 degrees C, respectively. The stoichiometry of both proteinase-inhibitor complexes is 1:1. The amino acid sequence of RTI consists of 60 amino acid residues, corresponding to an M(r) of about 6.7 kDa. The P1-P1' reactive site bond has been tentatively identified at position Arg20-Ile21. RTI shows no similarity to other serine proteinase inhibitors except the low molecular weight mustard trypsin inhibitor (MTI-2). RTI and MTI-2 could be members of a new class of plant serine proteinase inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites / genetics
  • Brassica / chemistry*
  • Brassica / genetics
  • Molecular Sequence Data
  • Mustard Plant / chemistry
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / isolation & purification*
  • Plants, Medicinal
  • Seeds / chemistry
  • Sequence Homology, Amino Acid
  • Trypsin Inhibitors / chemistry
  • Trypsin Inhibitors / genetics
  • Trypsin Inhibitors / isolation & purification*

Substances

  • Plant Proteins
  • Trypsin Inhibitors

Associated data

  • GENBANK/P80301