ID   CYTA_THETS              Reviewed;          43 AA.
AC   P81063;
DT   15-JUL-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-JUL-1998, sequence version 1.
DT   25-MAY-2022, entry version 40.
DE   RecName: Full=Cytin chain A;
OS   Theromyzon tessulatum (Duck leech).
OC   Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Annelida; Clitellata;
OC   Hirudinea; Rhynchobdellida; Glossiphoniidae; Theromyzon.
OX   NCBI_TaxID=13286;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=9395320; DOI=10.1111/j.1432-1033.1997.t01-1-00733.x;
RA   Chopin V., Bilfinger T.V., Stefano G.B., Hatiar I., Salzet M.;
RT   "Amino-acid-sequence determination and biological activity of cytin, a
RT   naturally occurring specific chymotrypsin inhibitor from the leech
RT   Theromyzon tessulatum.";
RL   Eur. J. Biochem. 249:733-738(1997).
CC   -!- FUNCTION: Inhibitor of chymotrypsin.
CC   -!- SUBUNIT: Heterodimer of an A chain and a B chain, linked by a disulfide
CC       bond.
CC   -!- SIMILARITY: Belongs to the protease inhibitor I13 (potato type I serine
CC       protease inhibitor) family. {ECO:0000305}.
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DR   AlphaFoldDB; P81063; -.
DR   MEROPS; I15.011; -.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Protease inhibitor;
KW   Serine protease inhibitor.
FT   CHAIN           1..43
FT                   /note="Cytin chain A"
FT                   /id="PRO_0000217657"
FT   DISULFID        34
FT                   /note="Interchain"
SQ   SEQUENCE   43 AA;  4934 MW;  3842C29723EC8C09 CRC64;
     AEVNPPEAFN QDVDTYLKIF RNGRYPLDKM AVICSQTGFK LDK