Component

4-Pyridoxic acid

Oxidized B6 catabolite. Independently recorded entity or measured process. Linked claims specify compartment, assay and experimental scope.

6 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What acts on it

  1. Urinary 4-pyridoxic acid was unremarkable in four affected children consuming normal dietary B6 despite markedly elevated plasma PLP.

    Tissue-nonspecific alkaline phosphatase ALPL / TNAP → 4-Pyridoxic acid source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Fourteen hypophosphatasia patients compared with 38 controls; urinary catabolite studied in four affected children.
    exposure
    Endogenous ALPL enzyme deficiency; ordinary dietary B6 in urinary subset.
    limitations
    Small subset; normal urinary excretion does not prove normal every-tissue metabolism.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    The circulating vitamin and its urinary breakdown product told different stories.
    primary_references
    [b6-whyte1985] Markedly increased circulating pyridoxal-5'-phosphate levels in hypophosphatasia. Alkaline phosphatase acts in vitamin B6 metabolism (1985). https://pubmed.ncbi.nlm.nih.gov/4031070/ DOI: 10.1172/jci112031
    tissue_or_cell_type
    Human blood and whole-body measurements
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1621–1631

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Fourteen hypophosphatasia patients compared with 38 controls; urinary catabolite studied in four affected children. · source_derived_draft · unverified_draft

    ### b6-hpp-urinary-catabolite Urinary 4-pyridoxic acid was unremarkable in four affected children consuming normal dietary B6 despite markedly elevated plasma PLP. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The circulating vitamin and its urinary breakdown product told different stories. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Fourteen hypophosphatasia patients compared with 38 controls; urinary catabolite studied in four affected children. limitations: Small subset; normal urinary excretion does not prove normal every-tissue metabolism. exposure: Endogenous ALPL enzyme deficiency; ordinary dietary B6 in urinary subset. [b6-whyte1985] Markedly increased circulating pyridoxal-5'-phosphate levels in hypophosphatasia. Alkaline phosphatase acts in vitamin B6 metabolism (1985). https://pubmed.ncbi.nlm.nih.gov/4031070/ DOI: 10.1172/jci112031
    Complete structured claim and evidence

  2. Partially purified rat tissue NAD-dependent aldehyde-dehydrogenase activity oxidized PL to 4-pyridoxic acid; oxidase-null rats still excreted the acid.

    Rat NAD-dependent pyridoxal dehydrogenase activity → 4-Pyridoxic acid source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    NAD links niacin-derived redox chemistry to B6 catabolism in this rat assay.
    evidence_location
    Indexed abstract: partially purified rat enzyme and urinary metabolites
    experimental_model
    Rat tissue enzyme fractions and aldehyde-oxidase activity variants.
    exposure
    Partially purified activity; kinetic assays at pH 9.6.
    limitations
    Molecular isoenzyme and quantitative contribution in humans not established.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Rattus norvegicus
    plain_language
    Rat B6 breakdown had an alternative to aldehyde oxidase.
    primary_references
    [stanulovic1976] New pathway of conversion of pyridoxal to 4-pyridoxic acid. (1976). https://pubmed.ncbi.nlm.nih.gov/939227/ DOI: 10.1159/000458879
    tissue_or_cell_type
    Rat tissue enzyme fractions and urine

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 491–503

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rat tissue enzyme fractions and aldehyde-oxidase activity variants. · source_derived_draft · unverified_draft

    ### b6-transport-rat-pl-catabolism Partially purified rat tissue NAD-dependent aldehyde-dehydrogenase activity oxidized PL to 4-pyridoxic acid; oxidase-null rats still excreted the acid. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Rat B6 breakdown had an alternative to aldehyde oxidase. organism: Rattus norvegicus tissue_or_cell_type: Rat tissue enzyme fractions and urine experimental_model: Rat tissue enzyme fractions and aldehyde-oxidase activity variants. limitations: Molecular isoenzyme and quantitative contribution in humans not established. exposure: Partially purified activity; kinetic assays at pH 9.6. evidence_location: Indexed abstract: partially purified rat enzyme and urinary metabolites cross_nutrient: NAD links niacin-derived redox chemistry to B6 catabolism in this rat assay. [stanulovic1976] New pathway of conversion of pyridoxal to 4-pyridoxic acid. (1976). https://pubmed.ncbi.nlm.nih.gov/939227/ DOI: 10.1159/000458879
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. In 150 affected children/adolescents, mean plasma pyridoxal was 66.7 versus 37.1 nM in controls; mean 4-pyridoxic acid did not differ.

    Tissue-nonspecific alkaline phosphatase ALPL / TNAP → Pyridoxal source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Primary measurement study in 150 children/adolescents with hypophosphatasia and healthy pediatric comparators; adult observations separately discussed.
    exposure
    ALPL-related hypophosphatasia, variable clinical severity; plasma vitamers, not direct all-tissue cofactor measurement.
    limitations
    Cohort result cannot be transferred to every severe neonatal case; does not establish all-tissue sufficiency.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    ALPL impairment did not make circulating pyridoxal universally low in this pediatric cohort.
    primary_references
    [b6-whyte2022] Hypophosphatasia: Vitamin B6 status of affected children and adults (2022). https://pubmed.ncbi.nlm.nih.gov/34547524/ DOI: 10.1016/j.bone.2021.116204
    tissue_or_cell_type
    Human blood and whole-body measurements
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1633–1643

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Primary measurement study in 150 children/adolescents with hypophosphatasia and healthy pediatric comparators; adult observations separately discussed. · source_derived_draft · unverified_draft

    ### b6-hpp-pediatric-pyridoxal In 150 affected children/adolescents, mean plasma pyridoxal was 66.7 versus 37.1 nM in controls; mean 4-pyridoxic acid did not differ. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: ALPL impairment did not make circulating pyridoxal universally low in this pediatric cohort. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Primary measurement study in 150 children/adolescents with hypophosphatasia and healthy pediatric comparators; adult observations separately discussed. limitations: Cohort result cannot be transferred to every severe neonatal case; does not establish all-tissue sufficiency. exposure: ALPL-related hypophosphatasia, variable clinical severity; plasma vitamers, not direct all-tissue cofactor measurement. [b6-whyte2022] Hypophosphatasia: Vitamin B6 status of affected children and adults (2022). https://pubmed.ncbi.nlm.nih.gov/34547524/ DOI: 10.1016/j.bone.2021.116204
    Complete structured claim and evidence

  2. In the 2025 cohort, untreated HPP had higher serum PLP and PLP: PL ratios; severe perinatal disease had lower PL than benign perinatal disease and the lowest PA across subtypes.

    Tissue-nonspecific alkaline phosphatase ALPL / TNAP → Serum PLP to pyridoxal ratio source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Over 100 hypophosphatasia cases, serum vitamers and available CSF; supplementation/enzyme-replacement subgroups.
    exposure
    Observational clinical sampling by subtype and treatment; no randomized B6 efficacy comparison.
    limitations
    Observational subtype comparison; contextual difference from broader pediatric cohorts, not an editorial conflict.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Disease severity changes which B6 forms accumulate or become low.
    primary_references
    [b6-akitomo2025] Vitamin B6 Status in Hypophosphatasia: Association With Clinical Severity, Diagnostic Utility, and Effects on Vitamin B6 Metabolism by Supplementation and Enzyme Replacement Therapy (2025). https://pubmed.ncbi.nlm.nih.gov/40387451/ DOI: 10.1002/jimd.70036
    tissue_or_cell_type
    Human blood and whole-body measurements
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1645–1655

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Over 100 hypophosphatasia cases, serum vitamers and available CSF; supplementation/enzyme-replacement subgroups. · source_derived_draft · unverified_draft

    ### b6-hpp-severity-vitamer-pattern In the 2025 cohort, untreated HPP had higher serum PLP and PLP: PL ratios; severe perinatal disease had lower PL than benign perinatal disease and the lowest PA across subtypes. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Disease severity changes which B6 forms accumulate or become low. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Over 100 hypophosphatasia cases, serum vitamers and available CSF; supplementation/enzyme-replacement subgroups. limitations: Observational subtype comparison; contextual difference from broader pediatric cohorts, not an editorial conflict. exposure: Observational clinical sampling by subtype and treatment; no randomized B6 efficacy comparison. [b6-akitomo2025] Vitamin B6 Status in Hypophosphatasia: Association With Clinical Severity, Diagnostic Utility, and Effects on Vitamin B6 Metabolism by Supplementation and Enzyme Replacement Therapy (2025). https://pubmed.ncbi.nlm.nih.gov/40387451/ DOI: 10.1002/jimd.70036
    Complete structured claim and evidence

  3. RA patients had lower plasma PLP than controls but no significant difference in erythrocyte PLP, AST activation coefficient or urinary 4-pyridoxic acid.

    Rheumatoid arthritis disease activity → Plasma pyridoxal 5-prime-phosphate concentration source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Human cross-sectional comparison: 33 RA patients, 17 healthy controls; separate pair-fed rat adjuvant-arthritis experiment.
    exposure
    Human observational samples; rats studied at peak day 21 and chronic day 42 inflammation. Human arm shares recruitment program with supplementation study.
    limitations
    Cross-sectional association; disease, treatment and nutrition are not fully separable. Shared recruitment with related 2005 trial.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    A low blood-plasma result did not mean that every measured B6 compartment was low.
    primary_references
    [b6-chiang2005-inflammation] Inflammation causes tissue-specific depletion of vitamin B6 (2005). https://pubmed.ncbi.nlm.nih.gov/16277678/ DOI: 10.1186/ar1821
    tissue_or_cell_type
    Human blood and whole-body measurements
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1523–1533

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human cross-sectional comparison: 33 RA patients, 17 healthy controls; separate pair-fed rat adjuvant-arthritis experiment. · source_derived_draft · unverified_draft

    ### b6-ra-plasma-redcell-divergence RA patients had lower plasma PLP than controls but no significant difference in erythrocyte PLP, AST activation coefficient or urinary 4-pyridoxic acid. Condition category: biomarker_context nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A low blood-plasma result did not mean that every measured B6 compartment was low. organism: Homo sapiens tissue_or_cell_type: Human blood and whole-body measurements experimental_model: Human cross-sectional comparison: 33 RA patients, 17 healthy controls; separate pair-fed rat adjuvant-arthritis experiment. limitations: Cross-sectional association; disease, treatment and nutrition are not fully separable. Shared recruitment with related 2005 trial. exposure: Human observational samples; rats studied at peak day 21 and chronic day 42 inflammation. Human arm shares recruitment program with supplementation study. [b6-chiang2005-inflammation] Inflammation causes tissue-specific depletion of vitamin B6 (2005). https://pubmed.ncbi.nlm.nih.gov/16277678/ DOI: 10.1186/ar1821
    Complete structured claim and evidence

  4. Pyridoxal and 4-pyridoxic acid inhibited PLP binding to human serum albumin in vitro.

    Pyridoxal → PLP source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Indexed abstract: equilibrium dialysis and competition
    experimental_model
    Purified human serum albumin binding assays.
    exposure
    In-vitro binding-inhibition experiments.
    limitations
    Physiological competition magnitude and consequences were not established.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Related B6 molecules can compete in albumin-binding assays.
    primary_references
    [fonda1991] The binding of pyridoxal 5'-phosphate to human serum albumin. (1991). https://pubmed.ncbi.nlm.nih.gov/1898027/ DOI: 10.1016/0003-9861(91)90167-h
    tissue_or_cell_type
    Purified serum albumin

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 348–359

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human serum albumin binding assays. · source_derived_draft · unverified_draft

    ### b6-transport-albumin-competition Pyridoxal and 4-pyridoxic acid inhibited PLP binding to human serum albumin in vitro. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Related B6 molecules can compete in albumin-binding assays. organism: Homo sapiens tissue_or_cell_type: Purified serum albumin experimental_model: Purified human serum albumin binding assays. limitations: Physiological competition magnitude and consequences were not established. exposure: In-vitro binding-inhibition experiments. evidence_location: Indexed abstract: equilibrium dialysis and competition [fonda1991] The binding of pyridoxal 5'-phosphate to human serum albumin. (1991). https://pubmed.ncbi.nlm.nih.gov/1898027/ DOI: 10.1016/0003-9861(91)90167-h
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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