ID   BXB3_BOMMO              Reviewed;          90 AA.
AC   P26737;
DT   01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1992, sequence version 1.
DT   25-MAY-2022, entry version 99.
DE   RecName: Full=Bombyxin B-3;
DE            Short=BBX-B3;
DE   AltName: Full=4K-prothoracicotropic hormone;
DE            Short=4K-PTTH;
DE   Contains:
DE     RecName: Full=Bombyxin B-3 B chain;
DE   Contains:
DE     RecName: Full=Bombyxin B-3 A chain;
DE   Flags: Precursor;
GN   Name=BBXB3;
OS   Bombyx mori (Silk moth).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Hexapoda; Insecta; Pterygota;
OC   Neoptera; Endopterygota; Lepidoptera; Glossata; Ditrysia; Bombycoidea;
OC   Bombycidae; Bombycinae; Bombyx.
OX   NCBI_TaxID=7091;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8683595; DOI=10.1006/jmbi.1996.0370;
RA   Kondo H., Ino M., Suzuki A., Ishizaki H., Iwami M.;
RT   "Multiple gene copies for bombyxin, an insulin-related peptide of the
RT   silkmoth Bombyx mori: structural signs for gene rearrangement and
RT   duplication responsible for generation of multiple molecular forms of
RT   bombyxin.";
RL   J. Mol. Biol. 259:926-937(1996).
CC   -!- FUNCTION: Brain peptide responsible for activation of prothoracic
CC       glands to produce ecdysone in insects.
CC   -!- SUBUNIT: Heterodimer of a B chain and an A chain linked by two
CC       disulfide bonds.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- MISCELLANEOUS: Silk worm has two kinds of PTTH: 4K-PTTH and 22K-PTTH;
CC       there are many forms of 4K-PTTH.
CC   -!- SIMILARITY: Belongs to the insulin family. {ECO:0000305}.
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DR   EMBL; D00778; BAA00674.1; -; Genomic_DNA.
DR   PIR; S69491; S69491.
DR   AlphaFoldDB; P26737; -.
DR   HOGENOM; CLU_125164_2_0_1; -.
DR   InParanoid; P26737; -.
DR   Proteomes; UP000005204; Unassembled WGS sequence.
DR   GO; GO:0005615; C:extracellular space; IEA:InterPro.
DR   GO; GO:0008083; F:growth factor activity; IEA:InterPro.
DR   GO; GO:0005179; F:hormone activity; IEA:UniProtKB-KW.
DR   InterPro; IPR017097; Bombyxin.
DR   InterPro; IPR027285; Bombyxin_B.
DR   InterPro; IPR016179; Insulin-like.
DR   InterPro; IPR036438; Insulin-like_sf.
DR   InterPro; IPR022353; Insulin_CS.
DR   InterPro; IPR022352; Insulin_family.
DR   Pfam; PF00049; Insulin; 2.
DR   PIRSF; PIRSF037038; Bombyxin; 1.
DR   PIRSF; PIRSF500313; Bombyxin_B; 1.
DR   PRINTS; PR02003; BOMBYXIN.
DR   PRINTS; PR00276; INSULINFAMLY.
DR   SMART; SM00078; IlGF; 1.
DR   SUPFAM; SSF56994; SSF56994; 1.
DR   PROSITE; PS00262; INSULIN; 1.
PE   3: Inferred from homology;
KW   Cleavage on pair of basic residues; Disulfide bond; Hormone;
KW   Reference proteome; Secreted; Signal.
FT   SIGNAL          1..20
FT                   /evidence="ECO:0000255"
FT   PEPTIDE         21..46
FT                   /note="Bombyxin B-3 B chain"
FT                   /id="PRO_0000015995"
FT   PROPEP          49..67
FT                   /note="C peptide like"
FT                   /id="PRO_0000015996"
FT   PEPTIDE         70..90
FT                   /note="Bombyxin B-3 A chain"
FT                   /id="PRO_0000015997"
FT   DISULFID        30..76
FT                   /note="Interchain (between B and A chains)"
FT                   /evidence="ECO:0000250"
FT   DISULFID        42..89
FT                   /note="Interchain (between B and A chains)"
FT                   /evidence="ECO:0000250"
FT   DISULFID        75..80
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   90 AA;  10152 MW;  0B9CDD449834CB29 CRC64;
     MMKTTIMFML VVVISLTYSS EEQEVARTYC GAHLANTLAD LCFGVEKRSG AQYAPYFWTR
     QYLGSRGKRG VVDECCFRPC TLDVLLSYCG