PROSITE documentation PDOC00257
Potato inhibitor I family signature


The potato inhibitor I family is one of the numerous families of serine proteinase inhibitors. Members of this protein family are found in plants; in the seeds of barley or beans [1,2,3], and in potato or tomato leaves where they accumulate in response to mechanical damage [4,5]. An inhibitor belonging to this family is also found in leech [6]. It is interesting to note that, currently, this is the only proteinase inhibitor family to be found both in plant and animal kingdoms.

Structurally these inhibitors are small (60 to 90 residues) and in contrast with other families of protease inhibitors, they lack disulfide bonds. They have a single inhibitory site. The consensus pattern we developed includes three out of the four residues conserved in all members of this family and is located in the N-terminal half.

Last update:

June 1994 / Text revised.


Technical section

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

POTATO_INHIBITOR, PS00285; Potato inhibitor I family signature  (PATTERN)


1AuthorsSvendsen I. Hejgaard J. Chavan J.K.
SourceCarlsberg Res. Commun. 49:493-502(1984).

2AuthorsSvendsen I. Boisen S. Hejgaard J.
SourceCarlsberg Res. Commun. 47:45-53(1982).

3AuthorsNozawa H. Yamagata H. Aizono Y. Yoshikawa M. Iwasaki T.
TitleThe complete amino acid sequence of a subtilisin inhibitor from adzuki beans (Vigna angularis).
SourceJ. Biochem. 106:1003-1008(1989).
PubMed ID2628417

4AuthorsCleveland T.E. Thornburg R.W. Ryan C.A.
SourcePlant Mol. Biol. 8:199-207(1987).

5AuthorsLee J.S. Brown W.E. Graham J.S. Pearce G. Fox E.A. Dreher T.W. Ahern K.G. Pearson G.D. Ryan C.A.
TitleMolecular characterization and phylogenetic studies of a wound-inducible proteinase inhibitor I gene in Lycopersicon species.
SourceProc. Natl. Acad. Sci. U.S.A. 83:7277-7281(1986).
PubMed ID3463966

6AuthorsSeemuller U. Eulitz M. Fritz H. Strobl A.
TitleStructure of the elastase-cathepsin G inhibitor of the leech Hirudo medicinalis.
SourceHoppe-Seyler's Z. Physiol. Chem. 361:1841-1846(1980).
PubMed ID6906312

7AuthorsZeng F.-Y. Qian R.-Q. Wang Y.
SourceFEBS Lett. 234:35-38(1988).

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