ID   LDHB_XENLA              Reviewed;         334 AA.
AC   P42119;
DT   01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2007, sequence version 2.
DT   03-AUG-2022, entry version 112.
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   Xenopus laevis (African clawed frog).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC   Batrachia; Anura; Pipoidea; Pipidae; Xenopodinae; Xenopus; Xenopus.
OX   NCBI_TaxID=8355;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Liver;
RX   PubMed=7937776; DOI=10.1073/pnas.91.20.9392;
RA   Tsuji S., Qureshi M.A., Hou E.W., Fitch W.M., Li S.S.-L.;
RT   "Evolutionary relationships of lactate dehydrogenases (LDHs) from mammals,
RT   birds, an amphibian, fish, barley, and bacteria: LDH cDNA sequences from
RT   Xenopus, pig, and rat.";
RL   Proc. Natl. Acad. Sci. U.S.A. 91:9392-9396(1994).
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.
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; U07176; AAA50434.1; -; mRNA.
DR   PIR; I51655; I51655.
DR   AlphaFoldDB; P42119; -.
DR   SMR; P42119; -.
DR   UniPathway; UPA00554; UER00611.
DR   Proteomes; UP000186698; Genome assembly.
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; Reference proteome.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000250"
FT   CHAIN           2..334
FT                   /note="L-lactate dehydrogenase B chain"
FT                   /id="PRO_0000168486"
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         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;  36358 MW;  60F32E7A521DFFB5 CRC64;
     MSTVQEKLIT NVCQDKAAKP TNKITIVGVG QVGMACAVSV LLKELADELA LVDILEDKLK
     GEVMDLQHGS LFLKTPTIVA DKDYSVTANS RIVVVTGGVP QQEGESRLNL VQRNVNVFKF
     IIPQVVKYSP DCIIIVVSNP VDILTYVTWK LSGLPQHRII GSGTNLDSAR FRHLISEKLG
     VHPSSCHGFI LGEHGDTSVA VWSGVNVAGV SLQSLKPEIG TDQDSCNWKE VHKKVVDSAY
     EVIKLKGYTN WAIGFSVAEI VESITKNLGR VHPVSTMVKG MYGIETEVFL SLPCVLNGNG
     LTSVINQKLK DDEVGQLQKS AETLWGIQKD LKDL