ID   CHSB_PETHY              Reviewed;         392 AA.
AC   P22924;
DT   01-AUG-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1991, sequence version 1.
DT   25-MAY-2022, entry version 90.
DE   RecName: Full=Chalcone synthase B;
DE            EC=2.3.1.74;
DE   AltName: Full=Naringenin-chalcone synthase B;
GN   Name=CHSB;
OS   Petunia hybrida (Petunia).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; lamiids; Solanales; Solanaceae; Petunioideae; Petunia.
OX   NCBI_TaxID=4102;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=cv. Violet 30; TISSUE=Leaf;
RX   PubMed=2806915; DOI=10.1016/0378-1119(89)90185-6;
RA   Koes R.E., Spelt C.E., van den Elzen P.J.M., Mol J.N.M.;
RT   "Cloning and molecular characterization of the chalcone synthase multigene
RT   family of Petunia hybrida.";
RL   Gene 81:245-257(1989).
CC   -!- FUNCTION: The primary product of this enzyme is 4,2',4',6'-
CC       tetrahydroxychalcone (also termed naringenin-chalcone or chalcone)
CC       which can under specific conditions spontaneously isomerize into
CC       naringenin.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=4-coumaroyl-CoA + 2 H(+) + 3 malonyl-CoA = 2',4,4',6'-
CC         tetrahydroxychalcone + 3 CO2 + 4 CoA; Xref=Rhea:RHEA:11128,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:16526, ChEBI:CHEBI:57287,
CC         ChEBI:CHEBI:57355, ChEBI:CHEBI:57384, ChEBI:CHEBI:77645; EC=2.3.1.74;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU10023};
CC   -!- PATHWAY: Secondary metabolite biosynthesis; flavonoid biosynthesis.
CC   -!- TISSUE SPECIFICITY: Expressed at low level in seedlings after
CC       illumination with UV light. No expression in flowers or tissue culture.
CC   -!- SIMILARITY: Belongs to the thiolase-like superfamily. Chalcone/stilbene
CC       synthases family. {ECO:0000305}.
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DR   EMBL; X14592; CAA32732.1; -; Genomic_DNA.
DR   PIR; JS0311; SYPJCB.
DR   AlphaFoldDB; P22924; -.
DR   SMR; P22924; -.
DR   UniPathway; UPA00154; -.
DR   GO; GO:0102128; F:chalcone synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0016210; F:naringenin-chalcone synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0009813; P:flavonoid biosynthetic process; IEA:UniProtKB-UniPathway.
DR   Gene3D; 3.40.47.10; -; 2.
DR   InterPro; IPR012328; Chalcone/stilbene_synt_C.
DR   InterPro; IPR001099; Chalcone/stilbene_synt_N.
DR   InterPro; IPR018088; Chalcone/stilbene_synthase_AS.
DR   InterPro; IPR011141; Polyketide_synthase_type-III.
DR   InterPro; IPR016039; Thiolase-like.
DR   PANTHER; PTHR11877; PTHR11877; 1.
DR   Pfam; PF02797; Chal_sti_synt_C; 1.
DR   Pfam; PF00195; Chal_sti_synt_N; 1.
DR   PIRSF; PIRSF000451; PKS_III; 1.
DR   SUPFAM; SSF53901; SSF53901; 2.
DR   PROSITE; PS00441; CHALCONE_SYNTH; 1.
PE   2: Evidence at transcript level;
KW   Acyltransferase; Flavonoid biosynthesis; Transferase.
FT   CHAIN           1..392
FT                   /note="Chalcone synthase B"
FT                   /id="PRO_0000216030"
FT   ACT_SITE        167
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10023"
SQ   SEQUENCE   392 AA;  42957 MW;  52B2F22515287274 CRC64;
     MKVENGQLQG WWAQRAEGPA KILAIGTATP FHWVDQNSYP DYYFRVTNSQ HLVDLKEKFR
     RICSKTMIKK RHMFLTEELL RKNPTLCSHN EPSLDIRQDI LVSEIPKLGK EAALKAIGEW
     GQPKSTITHL VFCTRSGVDM PGADCQLVKL LGLSPSVQRL MMYQQGCFAG GTMLRLAKDL
     AENNKGARVL VVCAESSAIG FRGPSEANVD NLIAQALFGD GAAALIIGSD PKPGLERPVF
     EIFSAAQTFV PNGDCHLALH LREMGLTFHC TKDVPPTIAK NVESCLIKAF EPLGISDWNS
     LFWILHPGGN AIVDQVESTL GLGPEKLRAT RNILSEYGNL SSACCLFILD EIRKKSAREG
     MRTSGDGLDL GVLLSFGPGL TIETVVLRSV PI