Ldhb

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0042867 pyruvate catabolic process	IBA GO_REF:0000033	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining pyruvate catabolic process as a direct annotation (IBA, GO_REF:0000033). Reason: pyruvate catabolic process is a direct process-level consequence of Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Propagation Review Root cause: SOURCE STALE OR MISSING Sources checked: PANTHER:PTN000166276 · PANTHER:PTN000166276 SOURCE STALE OR MISSING No IBD for GO:0042867 remains anywhere in the current PTHR43128 PAINT slice (snapshot rows dated through 2026-08-28), and the node named in the GOA WITH/FROM carries no assertions in it; the LDH-A/B/C node PTN000166277 now carries GO:0004459 and the directional GO:0019244 (lactate biosynthetic process from pyruvate) instead, so PAINT has re-scoped rather than dropped the pyruvate biology. The term itself remains well supported for rat Ldhb by the UniProt FUNCTION line and the enzyme's reaction, so only the phylogenetic support is stale. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0006089 lactate metabolic process	IBA GO_REF:0000033	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining lactate metabolic process as a direct annotation (IBA, GO_REF:0000033). Reason: lactate metabolic process is a direct process-level consequence of Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Propagation Review Root cause: SOURCE STALE OR MISSING Sources checked: PANTHER:PTN000166276 · PANTHER:PTN000166276 SOURCE STALE OR MISSING No IBD for GO:0006089 remains anywhere in the current PTHR43128 PAINT slice (snapshot rows dated through 2026-08-28), and the node named in the GOA WITH/FROM carries no assertions in it; the vertebrate LDH node PTN000166277 now carries the more specific GO:0019244 (lactate biosynthetic process from pyruvate). The annotation is independently grounded for rat Ldhb by a curated IDA (PMID:17447164) and an ISO from human LDHB, so only the phylogenetic support is stale. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0004459 L-lactate dehydrogenase (NAD+) activity	IBA GO_REF:0000033	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining L-lactate dehydrogenase (NAD+) activity as a direct annotation (IBA, GO_REF:0000033). Falcon deep research corroborates this as the core molecular function, noting LDHB is the heart-type subunit favoring the lactate-to-pyruvate direction with reduction of NAD+ to NADH. Reason: L-lactate dehydrogenase (NAD+) activity directly matches Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+). file:rat/Ldhb/Ldhb-deep-research-falcon.md The subunit-specific “directionality” framing in recent literature describes LDHB as supporting lactate oxidation to pyruvate with concomitant NAD+ → NADH, consistent with its canonical role in oxidative tissues that consume lactate.
GO:0005739 mitochondrion	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: mitochondrion is retained as contextual support for Ldhb, but it is not the core function (IBA, GO_REF:0000033). Falcon deep research flags that mitochondrial LDH localization is contested; in isolated rat soleus mitochondria, LDH activity was only ~0.7% of total and lactate alone did not support respiration, arguing against robust direct mitochondrial lactate oxidation. LDHB is predominantly a cytosolic enzyme. Reason: mitochondrion records localization context for Ldhb, not the defining molecular function, and the mitochondrial pool is minor and contested per the falcon evidence. Propagation Review Root cause: SOURCE STALE OR MISSING Sources checked: PANTHER:PTN000899413 · PANTHER:PTN000899413 SOURCE STALE OR MISSING No IBD for GO:0005739 remains anywhere in the current PTHR43128 PAINT slice (snapshot rows dated through 2026-08-28). The node the GOA WITH/FROM names still exists but now asserts cytosol (GO:0005829, seeded by fly, mouse Ldha/Ldhb/Ldhc and human LDHA/LDHB/LDHC), and the family root node asserts cytoplasm - so PAINT has re-scoped this lineage's localization from mitochondrion to the cytosol. That independently supports the contested, minor status of the mitochondrial pool recorded in the reason, and the row is kept only as non-core context. Supporting Evidence: file:rat/Ldhb/Ldhb-deep-research-falcon.md However, a direct rat mitochondrial preparation study in soleus muscle found LDH activity in the mitochondrial fraction to be only 0.7% of total activity and reported no detectable mitochondrial respiration on lactate alone.
GO:0003824 catalytic activity	IEA GO_REF:0000002	MODIFY	Summary: catalytic activity captures part of Ldhb biology, but a more specific replacement better represents the direct role (IEA, GO_REF:0000002). Reason: catalytic activity is directionally related to Ldhb but should be replaced by the more specific term(s): L-lactate dehydrogenase (NAD+) activity. Proposed replacements: L-lactate dehydrogenase (NAD+) activity Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0004459 L-lactate dehydrogenase (NAD+) activity	IEA GO_REF:0000120	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining L-lactate dehydrogenase (NAD+) activity as a direct annotation (IEA, GO_REF:0000120). Reason: L-lactate dehydrogenase (NAD+) activity directly matches Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005737 cytoplasm	IEA GO_REF:0000120	KEEP AS NON CORE	Summary: cytoplasm is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000120). Reason: cytoplasm records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005743 mitochondrial inner membrane	IEA GO_REF:0000120	KEEP AS NON CORE	Summary: mitochondrial inner membrane is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000120). Reason: mitochondrial inner membrane records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0016491 oxidoreductase activity	IEA GO_REF:0000002	MODIFY	Summary: oxidoreductase activity captures part of Ldhb biology, but a more specific replacement better represents the direct role (IEA, GO_REF:0000002). Reason: oxidoreductase activity is directionally related to Ldhb but should be replaced by the more specific term(s): L-lactate dehydrogenase (NAD+) activity. Proposed replacements: L-lactate dehydrogenase (NAD+) activity Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor	IEA GO_REF:0000002	MODIFY	Summary: oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor captures part of Ldhb biology, but a more specific replacement better represents the direct role (IEA, GO_REF:0000002). Reason: oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor is directionally related to Ldhb but should be replaced by the more specific term(s): L-lactate dehydrogenase (NAD+) activity. Proposed replacements: L-lactate dehydrogenase (NAD+) activity Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0019674 NAD+ metabolic process	IEA GO_REF:0000117	KEEP AS NON CORE	Summary: NAD+ metabolic process is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000117). Reason: NAD+ metabolic process is biologically related to Ldhb, but it is broader, downstream, or regulatory context relative to NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0051287 NAD binding	IEA GO_REF:0000117	KEEP AS NON CORE	Summary: NAD binding is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000117). Reason: NAD binding records cofactor, substrate, or interaction context for Ldhb, but the curated core role is NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005829 cytosol	IEA GO_REF:0000120	KEEP AS NON CORE	Summary: cytosol is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000120). Reason: cytosol records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0006089 lactate metabolic process	IEA GO_REF:0000120	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining lactate metabolic process as a direct annotation (IEA, GO_REF:0000120). Reason: lactate metabolic process is a direct process-level consequence of Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0042802 identical protein binding	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: identical protein binding is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000107). Reason: identical protein binding records cofactor, substrate, or interaction context for Ldhb, but the curated core role is NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0045121 membrane raft	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: membrane raft is an electronic (IEA, GO_REF:0000107) localization annotation. The cited UniProt FUNCTION text concerns catalysis only and provides no direct evidence for membrane-raft localization, and no raft-specific experimental evidence was found in the reviewed literature or falcon deep research. It is retained as a low-confidence, non-core localization pending direct evidence. Reason: membrane raft is an unverified pipeline localization annotation; there is no direct raft evidence in the available sources, so it is kept as non-core context rather than a defining function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:1990204 oxidoreductase complex	IEA GO_REF:0000107	KEEP AS NON CORE	Summary: oxidoreductase complex is retained as contextual support for Ldhb, but it is not the core function (IEA, GO_REF:0000107). Reason: oxidoreductase complex records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0042802 identical protein binding	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: identical protein binding is retained as contextual support for Ldhb, but it is not the core function (ISO, GO_REF:0000121). Reason: identical protein binding records cofactor, substrate, or interaction context for Ldhb, but the curated core role is NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005829 cytosol	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: cytosol is retained as contextual support for Ldhb, but it is not the core function (ISO, GO_REF:0000121). Reason: cytosol records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0004459 L-lactate dehydrogenase (NAD+) activity	ISO GO_REF:0000121	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining L-lactate dehydrogenase (NAD+) activity as a direct annotation (ISO, GO_REF:0000121). Reason: L-lactate dehydrogenase (NAD+) activity directly matches Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0006089 lactate metabolic process	ISO GO_REF:0000121	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining lactate metabolic process as a direct annotation (ISO, GO_REF:0000121). Reason: lactate metabolic process is a direct process-level consequence of Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0004459 L-lactate dehydrogenase (NAD+) activity	ISS GO_REF:0000024	ACCEPT	Summary: Ldhb's NAD-dependent interconversion of lactate and pyruvate supports retaining L-lactate dehydrogenase (NAD+) activity as a direct annotation (ISS, GO_REF:0000024). Reason: L-lactate dehydrogenase (NAD+) activity directly matches Ldhb's documented role in NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005743 mitochondrial inner membrane	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: mitochondrial inner membrane is retained as contextual support for Ldhb, but it is not the core function (ISS, GO_REF:0000024). Falcon deep research notes that LDH presence on the mitochondrial inner membrane (possibly via cardiolipin binding) has been reported in rat heart and skeletal muscle, but the association is contested and any mitochondrial pool is minor relative to the dominant cytosolic pool. Reason: mitochondrial inner membrane records a minor, contested localization context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+). file:rat/Ldhb/Ldhb-deep-research-falcon.md A biochemical study on heart- vs muscle-type LDH interactions with acidic phospholipids cites literature for LDH presence on/in the mitochondrial inner membrane, including in rat heart and skeletal muscle, and proposes cardiolipin-mediated binding influenced by pH and nucleotide/cofactor environment.
GO:0005743 mitochondrial inner membrane	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: mitochondrial inner membrane is retained as contextual support for Ldhb, but it is not the core function (ISO, GO_REF:0000121). Reason: mitochondrial inner membrane records localization or complex context for Ldhb, not the defining molecular function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0045121 membrane raft	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: membrane raft is an orthology-based (ISO, GO_REF:0000121) localization annotation transferred from another species. The cited UniProt FUNCTION text addresses catalysis only and provides no direct raft-localization evidence, and no raft-specific experimental evidence was found in the reviewed literature or falcon deep research. It is retained as a low-confidence, non-core localization. Reason: membrane raft is an unverified orthology-transferred localization annotation; there is no direct raft evidence in the available sources, so it is kept as non-core context rather than a defining function. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0019900 kinase binding	IPI PMID:17572440 M-LDH serves as a regulatory subunit of the cytosolic substr...	KEEP AS NON CORE	Summary: kinase binding is retained as contextual support for Ldhb, but it is not the core function (IPI, PMID:17572440). Reason: kinase binding records cofactor, substrate, or interaction context for Ldhb, but the curated core role is NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: PMID:17572440 Here, we show, using a range of empirically validated biochemical techniques, that the muscle form (M-LDH or LDH-A) and the heart form (H-LDH or LDH-B) of lactate dehydrogenase are physically associated with the liver cytosolic substrate-channelling complex such that M-LDH associates with NDPK-A, AMPK alpha1 and casein kinase 2 (CK2), whereas H-LDH associates with local NDPK-B.
GO:0004459 L-lactate dehydrogenase (NAD+) activity	IDA PMID:17447164 Effect of anabolic steroid nandrolone decanoate on the prope...	ACCEPT	Summary: The cited reference (PMID:17447164) is a study of nandrolone decanoate effects on pentose-phosphate and malate-aspartate shuttle enzymes (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, malic enzyme, NADP-linked isocitrate dehydrogenase, transketolase, NAD-linked malate dehydrogenase). The cached abstract does not mention lactate dehydrogenase activity, and full text is unavailable, so the IDA evidence for this term cannot be verified from the accessible text. Reason: The cached record of PMID:17447164 is abstract-only, so this specific IDA assay cannot be re-verified from the accessible text; the curator will have read the full text. L-lactate dehydrogenase (NAD+) activity is the unquestioned core molecular function of LDHB, independently supported by IBA, ISO, ISS and IEA annotations in this review and by UniProt, so per curation guidelines the annotation is accepted and deferred to the curator rather than second-guessed. Supporting Evidence: PMID:17447164 Nandrolone decanoate (ND) is an anabolic steroid, modified to enhance anabolic rather than androgenic actions. The physiological effects of ND treatment are often used in various aspects of medical practice. UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0006089 lactate metabolic process	IDA PMID:17447164 Effect of anabolic steroid nandrolone decanoate on the prope...	ACCEPT	Summary: The cited reference (PMID:17447164) is a study of nandrolone decanoate effects on pentose-phosphate and malate-aspartate shuttle enzymes and does not mention lactate dehydrogenase or lactate metabolism in the cached abstract; full text is unavailable, so the IDA evidence for this term cannot be verified from the accessible text. Reason: The cached record of PMID:17447164 is abstract-only, so this specific IDA assay cannot be re-verified from the accessible text; the curator will have read the full text. Lactate metabolic process is the core biological process of LDHB, independently supported by IBA, ISO and IEA annotations in this review, so per curation guidelines the annotation is accepted and deferred to the curator rather than second-guessed. Supporting Evidence: PMID:17447164 Nandrolone decanoate (ND) is an anabolic steroid, modified to enhance anabolic rather than androgenic actions. The physiological effects of ND treatment are often used in various aspects of medical practice. UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0019674 NAD+ metabolic process	IDA PMID:17447164 Effect of anabolic steroid nandrolone decanoate on the prope...	KEEP AS NON CORE	Summary: The cited reference (PMID:17447164) is a study of nandrolone decanoate effects on pentose-phosphate and malate-aspartate shuttle enzymes and does not mention lactate dehydrogenase in the cached abstract; full text is unavailable, so the IDA evidence for this term cannot be verified from the accessible text. Reason: The cached record of PMID:17447164 is abstract-only, so this specific IDA assay cannot be re-verified from the accessible text; the curator will have read the full text. LDHB genuinely interconverts NAD+ and NADH as part of its catalytic cycle, so the term is not wrong, but NAD+ metabolic process is a side classification rather than the core function; kept as non-core, consistent with the IEA annotation of the same term in this review. Supporting Evidence: PMID:17447164 Nandrolone decanoate (ND) is an anabolic steroid, modified to enhance anabolic rather than androgenic actions. The physiological effects of ND treatment are often used in various aspects of medical practice. UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0051287 NAD binding	IDA PMID:17447164 Effect of anabolic steroid nandrolone decanoate on the prope...	KEEP AS NON CORE	Summary: The cited reference (PMID:17447164) is a study of nandrolone decanoate effects on pentose-phosphate and malate-aspartate shuttle enzymes and does not mention lactate dehydrogenase or its NAD binding in the cached abstract; full text is unavailable, so the IDA evidence for this term cannot be verified from the accessible text. Reason: The cached record of PMID:17447164 is abstract-only, so this specific IDA assay cannot be re-verified from the accessible text; the curator will have read the full text. NAD binding is a true property of LDHB (its NAD-dependent catalysis requires cofactor binding via the Rossmann fold) but is cofactor-binding context rather than the core function; kept as non-core, consistent with the IEA annotation of the same term in this review. Supporting Evidence: PMID:17447164 Nandrolone decanoate (ND) is an anabolic steroid, modified to enhance anabolic rather than androgenic actions. The physiological effects of ND treatment are often used in various aspects of medical practice. UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0004457 lactate dehydrogenase activity	IDA PMID:7138505 Purification and radioimmunoassay of rat lactate dehydrogena...	MODIFY	Summary: lactate dehydrogenase activity (GO:0004457) is the generic, stereochemically unspecified parent class (lactate + NAD+ = pyruvate + NADH). The characterized activity of the LDH-B (heart-type) subunit is specifically the L-lactate/NAD+ reaction, captured more precisely by GO:0004459. For consistency with the other catalytic-activity annotations modified in this review, this is updated to the more specific term. Reason: GO:0004457 is the L-stereochemistry-agnostic parent term; GO:0004459 (L-lactate dehydrogenase (NAD+) activity) is the more specific term that matches the documented L-lactate/NAD+ activity of the LDHB subunit. (Note GO:0004459 is not a direct child of GO:0004457 in the GO hierarchy — they sit in parallel CH-OH oxidoreductase branches — but GO:0004459 is the more specific and accurate term for this enzyme.) Proposed replacements: L-lactate dehydrogenase (NAD+) activity Supporting Evidence: PMID:7138505 We have developed procedures for purifying lactate dehydrogenase isoenzymes from rat tissues that involve two affinity-chromatography steps and that facilitate the isolation of milligram quantities of highly purified proteins within 2--3 days.
GO:0005515 protein binding	IPI PMID:7138505 Purification and radioimmunoassay of rat lactate dehydrogena...	REMOVE	Summary: protein binding is an uninformative generic MF term. The only well-characterized protein-protein interaction of LDHB is its assembly into LDH homotetramers (and heterotetramers with LDHA), which is already captured by the more informative term GO:0042802 (identical protein binding). The cited reference (PMID:7138505) is an isoenzyme purification methods paper that does not provide specific interaction evidence. Reason: Generic 'protein binding' adds no functional information. The cached abstract of PMID:7138505 (abstract-only) describes isoenzyme purification and subunit-specific immunoassays and supports no more specific molecular function than the subunit self-association already recorded by GO:0042802 identical protein binding from the same paper, so no replacement is proposed. Removal of the generic term does not mean that LDHB subunit interactions are in doubt. GOA no longer carries this row (retired). Supporting Evidence: file:rat/Ldhb/Ldhb-deep-research-falcon.md Mammalian LDH is a tetramer built from the two principal subunits LDHA (muscle-type; historically “M”) and LDHB (heart-type; historically “H”), producing a set of major isoenzymes that differ in catalytic properties and tissue distribution.
GO:0042802 identical protein binding	IDA PMID:7138505 Purification and radioimmunoassay of rat lactate dehydrogena...	KEEP AS NON CORE	Summary: identical protein binding is retained as contextual support for Ldhb, but it is not the core function (IDA, PMID:7138505). Reason: identical protein binding records cofactor, substrate, or interaction context for Ldhb, but the curated core role is NAD-dependent interconversion of lactate and pyruvate. Supporting Evidence: PMID:7138505 We have developed procedures for purifying lactate dehydrogenase isoenzymes from rat tissues that involve two affinity-chromatography steps and that facilitate the isolation of milligram quantities of highly purified proteins within 2--3 days.
GO:0004459 L-lactate dehydrogenase (NAD+) activity	ISO GO_REF:0000121	ACCEPT	Summary: ISO transfer of L-lactate dehydrogenase (NAD+) activity from human LDHB (UniProtKB:P07195); donor-split companion of the accepted ISO row from mouse Ldhb (MGI:96763). Reason: Human LDHB is the direct ortholog and the LDH-B catalytic activity is conserved; this is the core molecular function of Ldhb. Supporting Evidence: UniProtKB:P42123 FUNCTION: Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+).
GO:0005829 cytosol	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: ISO transfer of cytosol localization from human LDHB (UniProtKB:P07195); donor-split companion of the mouse-donor (MGI:96763) cytosol ISO row, kept as non-core context. Reason: LDHB is a soluble cytoplasmic enzyme and the cytosolic location is well founded, but localization is context rather than the defining activity. Supporting Evidence: UniProtKB:P42123 SUBCELLULAR LOCATION: Cytoplasm.
GO:0019244 pyruvate fermentation to lactate	IBA GO_REF:0000033	ACCEPT	Summary: IBA for pyruvate fermentation to lactate from the animal L-lactate dehydrogenase node PANTHER:PTN000166277, grounded on mouse Ldha (MGI:96759), mouse Ldhc (MGI:96764) and Drosophila Ldh (FBgn0001258). It appears alongside the retirement of the older IBA rows for pyruvate catabolic process and lactate metabolic process. Reason: LDH catalyses the single step that reduces pyruvate to L-lactate with NADH, so the enzyme directly performs the process; rat Ldhb lies inside the LDH clade and retains the same reversible chemistry. LDHB-rich isoenzymes favour lactate oxidation in oxidative tissues, which is a kinetic and physiological bias rather than a loss of the reductive activity, so it does not argue against the node placement. Supporting Evidence: UniProtKB:P42123 PATHWAY: Fermentation; pyruvate fermentation to lactate; (S)-lactate
GO:1990204 oxidoreductase complex	ISO GO_REF:0000121	KEEP AS NON CORE	Summary: ISO transfer of part_of oxidoreductase complex from human LDHB (UniProtKB:P07195); matches the existing IEA row for the same term, kept as non-core. Reason: The LDH tetramer is an oxidoreductase complex, so the term is correct, but it is a generic complex term that adds context rather than the core activity. Supporting Evidence: UniProtKB:P42123 SUBUNIT: Homotetramer.

Gene Description

Existing Annotations Review

Core Functions

Ldhb catalyzes the reversible NAD-dependent conversion between L-lactate and pyruvate.

References

Suggested Questions for Experts

Deep Research

Falcon

📚 Additional Documentation

Notes

📄 View Raw YAML