ID   CYTB_HELAN              Reviewed;         101 AA.
AC   Q10993;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   08-NOV-2023, entry version 81.
DE   RecName: Full=Cysteine proteinase inhibitor B;
DE   AltName: Full=Cystatin-B;
DE   AltName: Full=SCB;
OS   Helianthus annuus (Common sunflower).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; campanulids; Asterales; Asteraceae; Asteroideae;
OC   Heliantheae alliance; Heliantheae; Helianthus.
OX   NCBI_TaxID=4232;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Seed;
RX   PubMed=8827445; DOI=10.1093/oxfordjournals.jbchem.a021355;
RA   Kouzuma Y., Kawano K., Kimura M., Yamasaki N., Kadowaki T., Yamamoto K.;
RT   "Purification, characterization, and sequencing of two cysteine proteinase
RT   inhibitors, Sca and Scb, from sunflower (Helianthus annuus) seeds.";
RL   J. Biochem. 119:1106-1113(1996).
CC   -!- FUNCTION: Strong inhibitor of papain, ficin and cathepsin H, B and L.
CC   -!- SIMILARITY: Belongs to the cystatin family. {ECO:0000305}.
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DR   PIR; JC4792; JC4792.
DR   AlphaFoldDB; Q10993; -.
DR   SMR; Q10993; -.
DR   MEROPS; I25.057; -.
DR   EnsemblPlants; mRNA:HanXRQr2_Chr02g0085281; CDS:HanXRQr2_Chr02g0085281.1; HanXRQr2_Chr02g0085281.
DR   Gramene; mRNA:HanXRQr2_Chr02g0085281; CDS:HanXRQr2_Chr02g0085281.1; HanXRQr2_Chr02g0085281.
DR   GO; GO:0004869; F:cysteine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   CDD; cd00042; CY; 1.
DR   Gene3D; 3.10.450.10; -; 1.
DR   InterPro; IPR000010; Cystatin_dom.
DR   InterPro; IPR046350; Cystatin_sf.
DR   InterPro; IPR018073; Prot_inh_cystat_CS.
DR   PANTHER; PTHR47373; CYSTEINE PROTEINASE INHIBITOR 2; 1.
DR   PANTHER; PTHR47373:SF1; CYSTEINE PROTEINASE INHIBITOR 2; 1.
DR   Pfam; PF16845; SQAPI; 1.
DR   SMART; SM00043; CY; 1.
DR   SUPFAM; SSF54403; Cystatin/monellin; 1.
DR   PROSITE; PS00287; CYSTATIN; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Protease inhibitor; Thiol protease inhibitor.
FT   CHAIN           1..101
FT                   /note="Cysteine proteinase inhibitor B"
FT                   /id="PRO_0000207155"
SQ   SEQUENCE   101 AA;  11186 MW;  789CD3E9611CBFD1 CRC64;
     IPGGRTKVKN VKTDTEIQQL GSYSVDEYNR LQRTKKTGAG DLKFSQVIAA ETQVVAGTKY
     YLKIEAITKG GKMKVFDAEV VVQSWKHSKK LLGFKPAPVD K
//