PROSITE documentation PDOC00255
Soybean trypsin inhibitor (Kunitz) protease inhibitors family signature


The soybean trypsin inhibitor (Kunitz) family [1] is one of the numerous families of proteinase inhibitors. It comprise plant proteins which have inhibitory activity against serine proteinases from the trypsin and subtilisin families, thiol proteinases and aspartic proteinases as well as some proteins that are probably involved in seed storage. This family is currently known to group the following proteins:

  • Trypsin inhibitors A, B, C, KTI1, and KTI2 from soybean.
  • Trypsin inhibitor DE3 from coral beans (Erythrina sp.).
  • Trypsin inhibitor DE5 from sandal bead tree.
  • Trypsin inhibitors 1A (WTI-1A), 1B (WTI-1B), and 2 (WTI-2) from goa bean.
  • Trypsin inhibitor from Acacia confusa.
  • Trypsin inhibitor from silk tree.
  • Chymotrypsin inhibitor 3 (WCI-3) from goa bean.
  • Cathepsin D inhibitors PDI and NDI from potato [2], which inhibit both cathepsin D (aspartic proteinase) and trypsin.
  • α-amylase/subtilisin inhibitors from barley and wheat.
  • Albumin-1 (WBA-1) from goa bean seeds [3].
  • Miraculin from Richadella dulcifica [4], a sweet taste protein.
  • Sporamin from sweet potato [5], the major tuberous root protein.
  • Thiol proteinase inhibitor PCPI 8.3 (P340) from potato tuber [6].
  • Wound responsive protein gwin3 from poplar tree [7].
  • 21 Kd seed protein from cocoa [8].

All these proteins contain from 170 to 200 amino acid residues and one or two intrachain disulfide bonds. The best conserved region is found in their N-terminal section and is used as a signature pattern.

Last update:

April 2006 / Pattern revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

SOYBEAN_KUNITZ, PS00283; Soybean trypsin inhibitor (Kunitz) protease inhibitors family signature  (PATTERN)


1AuthorsLaskowski M. Jr. Kato I.
TitleProtein inhibitors of proteinases.
SourceAnnu. Rev. Biochem. 49:593-626(1980).
PubMed ID6996568

2AuthorsRitonja A. Krizaj I. Mesko P. Kopitar M. Lucovnik P. Strukelj B. Pungercar J. Buttle D.J. Barrett A.J. Turk V.
TitleThe amino acid sequence of a novel inhibitor of cathepsin D from potato.
SourceFEBS Lett. 267:13-15(1990).
PubMed ID2365079

3AuthorsKortt A.A. Strike P.M. De Jersey J.
TitleAmino acid sequence of a crystalline seed albumin (winged bean albumin-1) from Psophocarpus tetragonolobus (L.) DC. Sequence similarity with Kunitz-type seed inhibitors and 7S storage globulins.
SourceEur. J. Biochem. 181:403-408(1989).
PubMed ID2653830

4AuthorsTheerasilp S. Hitotsuya H. Nakajo S. Nakaya K. Nakamura Y. Kurihara Y.
TitleComplete amino acid sequence and structure characterization of the taste-modifying protein, miraculin.
SourceJ. Biol. Chem. 264:6655-6659(1989).
PubMed ID2708331

5AuthorsHattori T. Yoshida N. Nakamura K.
TitleStructural relationship among the members of a multigene family coding for the sweet potato tuberous root storage protein.
SourcePlant Mol. Biol. 13:563-572(1989).
PubMed ID2491673

6AuthorsKrizaj I. Drobnic-Kosorok M. Brzin J. Jerala R. Turk V.
TitleThe primary structure of inhibitor of cysteine proteinases from potato.
SourceFEBS Lett. 333:15-20(1993).
PubMed ID8224155

7AuthorsBradshaw H.D. Jr. Hollick J.B. Parsons T.J. Clarke H.R.G. Gordon M.P.
TitleSystemically wound-responsive genes in poplar trees encode proteins similar to sweet potato sporamins and legume Kunitz trypsin inhibitors.
SourcePlant Mol. Biol. 14:51-59(1990).
PubMed ID2101311

8AuthorsTai H. McHenry L. Fritz P.J. Furtek D.B.
TitleNucleic acid sequence of a 21 kDa cocoa seed protein with homology to the soybean trypsin inhibitor (Kunitz) family of protease inhibitors.
SourcePlant Mol. Biol. 16:913-915(1991).
PubMed ID1859871

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