ID   CYT1_ACTDE              Reviewed;         116 AA.
AC   Q6TPK4;
DT   20-APR-2010, integrated into UniProtKB/Swiss-Prot.
DT   05-JUL-2004, sequence version 1.
DT   25-MAY-2022, entry version 47.
DE   RecName: Full=Cysteine proteinase inhibitor 1 {ECO:0000303|PubMed:14697268};
DE            Short=KCPI1 {ECO:0000303|PubMed:14697268};
DE   AltName: Full=Phytocystatin {ECO:0000312|EMBL:AAR92223.1};
DE   AltName: Allergen=Act d 4;
DE   Flags: Precursor;
OS   Actinidia deliciosa (Kiwi).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; Ericales; Actinidiaceae; Actinidia.
OX   NCBI_TaxID=3627;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:AAR92223.1}
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 27-46, FUNCTION, AND MASS
RP   SPECTROMETRY.
RC   STRAIN=cv. Hayward {ECO:0000269|PubMed:14697268};
RC   TISSUE=Fruit cortical tissue {ECO:0000312|EMBL:AAR92223.1};
RX   PubMed=14697268; DOI=10.1016/j.phytochem.2003.09.019;
RA   Rassam M., Laing W.A.;
RT   "Purification and characterization of phytocystatins from kiwifruit cortex
RT   and seeds.";
RL   Phytochemistry 65:19-30(2004).
RN   [2]
RP   PROTEIN SEQUENCE OF 27-41, FUNCTION, MASS SPECTROMETRY, GLYCOSYLATION, AND
RP   ALLERGEN.
RX   PubMed=19885843; DOI=10.1002/mnfr.200900035;
RA   Popovic M.M., Milovanovic M., Burazer L., Vuckovic O.,
RA   Hoffmann-Sommergruber K., Knulst A.C., Lindner B., Petersen A., Jankov R.,
RA   Gavrovic-Jankulovic M.;
RT   "Cysteine proteinase inhibitor Act d 4 is a functional allergen
RT   contributing to the clinical symptoms of kiwifruit allergy.";
RL   Mol. Nutr. Food Res. 54:373-380(2010).
RN   [3] {ECO:0000305}
RP   PROTEIN SEQUENCE OF 27-37, AND ALLERGEN.
RC   STRAIN=cv. Hayward {ECO:0000269|PubMed:15536427};
RC   TISSUE=Fruit {ECO:0000269|PubMed:15536427};
RX   PubMed=15536427; DOI=10.1016/j.jaci.2004.07.016;
RA   Bublin M., Mari A., Ebner C., Knulst A., Scheiner O.,
RA   Hoffmann-Sommergruber K., Breiteneder H., Radauer C.;
RT   "IgE sensitization profiles toward green and gold kiwifruits differ among
RT   patients allergic to kiwifruit from 3 European countries.";
RL   J. Allergy Clin. Immunol. 114:1169-1175(2004).
CC   -!- FUNCTION: Specific inhibitor of papain family cysteine proteinases.
CC       Inhibits papain, chymopapain, bromelain, ficin, human cathepsins B, H
CC       and L, actinidain and house dustmite endopeptidase 1, but does not
CC       inhibit human bleomycin hydrolase. Inhibits papain with an IC(50) of
CC       2.47 nM. Does not inhibit cysteine proteinases belonging to other
CC       families including clostripain, streptopain and calpain.
CC       {ECO:0000269|PubMed:14697268, ECO:0000269|PubMed:19885843}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P01035}.
CC   -!- PTM: Glycosylated. {ECO:0000269|PubMed:19885843}.
CC   -!- MASS SPECTROMETRY: Mass=10928; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:14697268};
CC   -!- MASS SPECTROMETRY: Mass=10902.5; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:14697268, ECO:0000269|PubMed:19885843};
CC   -!- MASS SPECTROMETRY: Mass=11055.2; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:14697268, ECO:0000269|PubMed:19885843};
CC   -!- ALLERGEN: Causes an allergic reaction in human. Binds IgE. Induces
CC       basophil activation. {ECO:0000269|PubMed:15536427,
CC       ECO:0000269|PubMed:19885843}.
CC   -!- SIMILARITY: Belongs to the cystatin family. Phytocystatin subfamily.
CC       {ECO:0000255}.
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DR   EMBL; AY390352; AAR92223.1; -; mRNA.
DR   AlphaFoldDB; Q6TPK4; -.
DR   SMR; Q6TPK4; -.
DR   Allergome; 2404; Act d 4.
DR   Allergome; 3587; Act d 4.0101.
DR   MEROPS; I25.033; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004869; F:cysteine-type endopeptidase inhibitor activity; IDA:UniProtKB.
DR   GO; GO:0006952; P:defense response; IEA:UniProtKB-KW.
DR   CDD; cd00042; CY; 1.
DR   InterPro; IPR000010; Cystatin_dom.
DR   InterPro; IPR046350; Cystatin_sf.
DR   Pfam; PF16845; SQAPI; 1.
DR   SMART; SM00043; CY; 1.
DR   SUPFAM; SSF54403; SSF54403; 1.
PE   1: Evidence at protein level;
KW   Allergen; Direct protein sequencing; Glycoprotein; Plant defense;
KW   Protease inhibitor; Secreted; Signal; Thiol protease inhibitor.
FT   SIGNAL          1..26
FT                   /evidence="ECO:0000269|PubMed:14697268,
FT                   ECO:0000269|PubMed:15536427, ECO:0000269|PubMed:19885843"
FT   CHAIN           27..116
FT                   /note="Cysteine proteinase inhibitor 1"
FT                   /evidence="ECO:0000269|PubMed:14697268,
FT                   ECO:0000269|PubMed:15536427"
FT                   /id="PRO_0000393866"
FT   DOMAIN          30..89
FT                   /note="Cystatin"
FT                   /evidence="ECO:0000255"
FT   MOTIF           73..77
FT                   /note="Secondary area of contact"
FT                   /evidence="ECO:0000250|UniProtKB:P01035"
FT   SITE            30
FT                   /note="Reactive site"
FT                   /evidence="ECO:0000250|UniProtKB:P01035"
FT   CARBOHYD        109
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CONFLICT        37
FT                   /note="S -> E (in Ref. 3; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   116 AA;  12756 MW;  4BFAF54F8935B59B CRC64;
     MVPKPLSLLL FLLLALSAAV VGGRKLVAAG GWRPIESLNS AEVQDVAQFA VSEHNKQAND
     ELQYQSVVRG YTQVVAGTNY RLVIAAKDGA VVGNYEAVVW DKPWMHFRNL TSFRKV