ID   ISOTI_SPIOL             Reviewed;          20 AA.
AC   P86549;
DT   13-JUL-2010, integrated into UniProtKB/Swiss-Prot.
DT   13-JUL-2010, sequence version 1.
DT   25-MAY-2022, entry version 14.
DE   RecName: Full=Kunitz-type serine protease inhibitor SOTI;
DE   AltName: Full=Trypsin inhibitor {ECO:0000303|PubMed:19232057};
DE            Short=SOTI {ECO:0000303|PubMed:19232057};
DE   Flags: Fragments;
OS   Spinacia oleracea (Spinach).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   Caryophyllales; Chenopodiaceae; Chenopodioideae; Anserineae; Spinacia.
OX   NCBI_TaxID=3562;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE, FUNCTION, AND BIOPHYSICOCHEMICAL PROPERTIES.
RC   TISSUE=Seed {ECO:0000269|PubMed:19232057};
RX   PubMed=19232057; DOI=10.1134/s0006297909010167;
RA   Kang Z., Jiang J.H., Wang D., Liu K., Du L.F.;
RT   "Kunitz-type trypsin inhibitor with high stability from Spinacia oleracea
RT   L. seeds.";
RL   Biochemistry (Mosc.) 74:102-109(2009).
CC   -!- FUNCTION: Inhibitor of bovine trypsin with a Ki of 2.3 uM. Inhibits 50%
CC       of the proteolytic activity of P.rapae larvae midgut extract at a
CC       concentration of 20 ug/ml. Inhibitory activity against trypsin is
CC       reduced by 43% in the presence of the lysine modifier TBNS, but is not
CC       affected by dithiothreitol. {ECO:0000269|PubMed:19232057}.
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       pH dependence:
CC         Stable at pH values ranging from 3.0-11.0 at 4 degrees Celsius.
CC         {ECO:0000269|PubMed:19232057};
CC       Temperature dependence:
CC         Thermostable when incubated at pH 8.0 at temperatures between 40 and
CC         100 degrees Celsius. {ECO:0000269|PubMed:19232057};
CC   -!- MISCELLANEOUS: On the 2D-gel the determined pI of this protein is:
CC       4.05, its MW is: 23 kDa. {ECO:0000269|PubMed:19232057}.
CC   -!- SIMILARITY: Belongs to the leguminous Kunitz-type inhibitor family.
CC       {ECO:0000269|PubMed:19232057}.
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DR   AlphaFoldDB; P86549; -.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IDA:UniProtKB.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Protease inhibitor; Serine protease inhibitor.
FT   CHAIN           <1..>20
FT                   /note="Kunitz-type serine protease inhibitor SOTI"
FT                   /id="PRO_0000395669"
FT   NON_CONS        9..10
FT                   /evidence="ECO:0000303|PubMed:19232057"
FT   NON_TER         1
FT                   /evidence="ECO:0000303|PubMed:19232057"
FT   NON_TER         20
FT                   /evidence="ECO:0000303|PubMed:19232057"
SQ   SEQUENCE   20 AA;  2045 MW;  38D90651D94C361E CRC64;
     TVAACNSPKV GLDSDAELVR