ID   LDHB_POLSE              Reviewed;         334 AA.
AC   Q1EG91;
DT   28-NOV-2006, integrated into UniProtKB/Swiss-Prot.
DT   11-JUL-2006, sequence version 1.
DT   03-AUG-2022, entry version 62.
DE   RecName: Full=L-lactate dehydrogenase B chain;
DE            Short=LDH-B;
DE            EC=1.1.1.27 {ECO:0000250|UniProtKB:P07195};
GN   Name=ldhb;
OS   Polypterus senegalus (Senegal bichir).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Actinopterygii; Polypteriformes; Polypteridae; Polypterus.
OX   NCBI_TaxID=55291;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Ovary;
RA   Tsoi S.C.-M.;
RT   "Phylogenomic analysis and evolutionary conservation of the lactate
RT   dehydrogenase gene family in actinopterygians.";
RL   Submitted (MAY-2004) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Interconverts simultaneously and stereospecifically pyruvate
CC       and lactate with concomitant interconversion of NADH and NAD(+).
CC       {ECO:0000250|UniProtKB:P07195}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(S)-lactate + NAD(+) = H(+) + NADH + pyruvate;
CC         Xref=Rhea:RHEA:23444, ChEBI:CHEBI:15361, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:16651, ChEBI:CHEBI:57540, ChEBI:CHEBI:57945; EC=1.1.1.27;
CC         Evidence={ECO:0000250|UniProtKB:P07195};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:23445;
CC         Evidence={ECO:0000250|UniProtKB:P07195};
CC       PhysiologicalDirection=right-to-left; Xref=Rhea:RHEA:23446;
CC         Evidence={ECO:0000250|UniProtKB:P07195};
CC   -!- PATHWAY: Fermentation; pyruvate fermentation to lactate; (S)-lactate
CC       from pyruvate: step 1/1. {ECO:0000250|UniProtKB:P07195}.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the LDH/MDH superfamily. LDH family.
CC       {ECO:0000305}.
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DR   EMBL; AY641475; AAV31764.1; -; mRNA.
DR   AlphaFoldDB; Q1EG91; -.
DR   SMR; Q1EG91; -.
DR   UniPathway; UPA00554; UER00611.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0004459; F:L-lactate dehydrogenase activity; IEA:UniProtKB-EC.
DR   GO; GO:0019752; P:carboxylic acid metabolic process; IEA:InterPro.
DR   Gene3D; 3.90.110.10; -; 1.
DR   HAMAP; MF_00488; Lactate_dehydrog; 1.
DR   InterPro; IPR001557; L-lactate/malate_DH.
DR   InterPro; IPR011304; L-lactate_DH.
DR   InterPro; IPR018177; L-lactate_DH_AS.
DR   InterPro; IPR022383; Lactate/malate_DH_C.
DR   InterPro; IPR001236; Lactate/malate_DH_N.
DR   InterPro; IPR015955; Lactate_DH/Glyco_Ohase_4_C.
DR   InterPro; IPR036291; NAD(P)-bd_dom_sf.
DR   Pfam; PF02866; Ldh_1_C; 1.
DR   Pfam; PF00056; Ldh_1_N; 1.
DR   PIRSF; PIRSF000102; Lac_mal_DH; 1.
DR   PRINTS; PR00086; LLDHDRGNASE.
DR   SUPFAM; SSF51735; SSF51735; 1.
DR   SUPFAM; SSF56327; SSF56327; 1.
DR   TIGRFAMs; TIGR01771; L-LDH-NAD; 1.
DR   PROSITE; PS00064; L_LDH; 1.
PE   2: Evidence at transcript level;
KW   Cytoplasm; NAD; Oxidoreductase.
FT   CHAIN           1..334
FT                   /note="L-lactate dehydrogenase B chain"
FT                   /id="PRO_0000260294"
FT   ACT_SITE        194
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000250"
FT   BINDING         30..58
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         100
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         107
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         139
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         139
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         170
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         249
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   334 AA;  36581 MW;  9A757B2389B5039E CRC64;
     MASVHEKLIS TVADCAPEQP RNKVTVVGVG QVGMACAFSI LSGNYADELA LVDVLEDKLE
     GEMMDLLHGS VFLKTRKIVA NKDYSVTANS RIVVVTAGAR QQEGESRLNL VQRNVNIFKH
     IIPQIVKYSP NCVIIVVSNP VDILTYITWK LSGLPKHRVI GSGCNLDSAR FRYMMAEKLG
     IHASSFHGWI LGEHGDSSVP VWSGANVAGV CLKSLNPNVG TDKDQENWKD VHKQVVDSAY
     KIIELKGYTN WAIGLSVADI IESLVKNLGR VHPVSTMVKN MYGINEEVFL SLPCVLNNCG
     VASVINVTLA DDEVAKLRKS AETLWNIQKD LKDV