Component

Human pyridoxal phosphatase / PDXP

Human chronophin; vitamin B6 phosphate phosphatase.

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 it acts on

  1. Catalytically active recombinant human pyridoxal phosphatase hydrolyzed pyridoxal-phosphate.

    Human pyridoxal phosphatase / PDXP → PLP source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Indexed abstract: cloning and substrate hydrolysis
    experimental_model
    Recombinant human pyridoxal phosphatase expressed in E. coli.
    exposure
    Recombinant-enzyme characterization.
    limitations
    Model-specific evidence; no dietary threshold or treatment benefit established.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    PDXP removes phosphate from a B6 vitamer.
    primary_references
    [jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200
    tissue_or_cell_type
    Purified recombinant human enzyme

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 256–267

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human pyridoxal phosphatase expressed in E. coli. · source_derived_draft · unverified_draft

    ### b6-transport-pdxp-plp Catalytically active recombinant human pyridoxal phosphatase hydrolyzed pyridoxal-phosphate. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: PDXP removes phosphate from a B6 vitamer. organism: Homo sapiens tissue_or_cell_type: Purified recombinant human enzyme experimental_model: Recombinant human pyridoxal phosphatase expressed in E. coli. limitations: Model-specific evidence; no dietary threshold or treatment benefit established. exposure: Recombinant-enzyme characterization. evidence_location: Indexed abstract: cloning and substrate hydrolysis [jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200
    Complete structured claim and evidence

  2. Catalytically active recombinant human pyridoxal phosphatase hydrolyzed pyridoxine-phosphate.

    Human pyridoxal phosphatase / PDXP → Pyridoxine 5-prime-phosphate source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Indexed abstract: cloning and substrate hydrolysis
    experimental_model
    Recombinant human pyridoxal phosphatase expressed in E. coli.
    exposure
    Recombinant-enzyme characterization.
    limitations
    Model-specific evidence; no dietary threshold or treatment benefit established.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    PDXP removes phosphate from a B6 vitamer.
    primary_references
    [jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200
    tissue_or_cell_type
    Purified recombinant human enzyme

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 269–280

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human pyridoxal phosphatase expressed in E. coli. · source_derived_draft · unverified_draft

    ### b6-transport-pdxp-pnp Catalytically active recombinant human pyridoxal phosphatase hydrolyzed pyridoxine-phosphate. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: PDXP removes phosphate from a B6 vitamer. organism: Homo sapiens tissue_or_cell_type: Purified recombinant human enzyme experimental_model: Recombinant human pyridoxal phosphatase expressed in E. coli. limitations: Model-specific evidence; no dietary threshold or treatment benefit established. exposure: Recombinant-enzyme characterization. evidence_location: Indexed abstract: cloning and substrate hydrolysis [jang2003] Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. (2003). https://pubmed.ncbi.nlm.nih.gov/14522954/ DOI: 10.1074/jbc.m309619200
    Complete structured claim and evidence

What acts on it

  1. Human erythrocyte pyridoxal phosphatase required divalent cations; magnesium activated PLP hydrolysis with Michaelis-Menten behavior.

    Mg2+ → Human pyridoxal phosphatase / PDXP source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Magnesium participates in both sides of B6 phosphate cycling.
    evidence_location
    Indexed abstract: divalent-cation kinetics at pH 7.4, 37 C
    experimental_model
    Purified human erythrocyte pyridoxal phosphatase kinetics.
    exposure
    pH 7.4, 37 C; Mg2+ titration.
    limitations
    Other metals also activated in vitro; does not establish net PLP response to changing dietary magnesium.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Magnesium supports B6 dephosphorylation as well as activation.
    primary_references
    [fonda1995] Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. (1995). https://pubmed.ncbi.nlm.nih.gov/7625842/ DOI: 10.1016/0003-9861(95)90018-7
    tissue_or_cell_type
    Erythrocyte enzyme

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 282–294

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human erythrocyte pyridoxal phosphatase kinetics. · source_derived_draft · unverified_draft

    ### b6-transport-pdxp-magnesium Human erythrocyte pyridoxal phosphatase required divalent cations; magnesium activated PLP hydrolysis with Michaelis-Menten behavior. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Magnesium supports B6 dephosphorylation as well as activation. organism: Homo sapiens tissue_or_cell_type: Erythrocyte enzyme experimental_model: Purified human erythrocyte pyridoxal phosphatase kinetics. limitations: Other metals also activated in vitro; does not establish net PLP response to changing dietary magnesium. exposure: pH 7.4, 37 C; Mg2+ titration. evidence_location: Indexed abstract: divalent-cation kinetics at pH 7.4, 37 C cross_nutrient: Magnesium participates in both sides of B6 phosphate cycling. [fonda1995] Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. (1995). https://pubmed.ncbi.nlm.nih.gov/7625842/ DOI: 10.1016/0003-9861(95)90018-7
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Polarized Caco-2 cells supplied apically with PM generated PL and released more PL basolaterally than apically.

    Pyridoxamine → Pyridoxal source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Results: Incubation with pyridoxamine; Figure 4
    experimental_model
    Polarized human Caco-2 monolayers; human intestinal lysates.
    exposure
    100 or 1000 nM PM; 6-48 h.
    limitations
    Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Enterocytes can process a precursor before releasing pyridoxal.
    primary_references
    [albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113
    tissue_or_cell_type
    Polarized Caco-2 monolayers

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 137–148

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Polarized human Caco-2 monolayers; human intestinal lysates. · source_derived_draft · unverified_draft

    ### b6-transport-enterocyte-pm-to-pl Polarized Caco-2 cells supplied apically with PM generated PL and released more PL basolaterally than apically. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Enterocytes can process a precursor before releasing pyridoxal. organism: Homo sapiens tissue_or_cell_type: Polarized Caco-2 monolayers experimental_model: Polarized human Caco-2 monolayers; human intestinal lysates. limitations: Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed. exposure: 100 or 1000 nM PM; 6-48 h. evidence_location: Results: Incubation with pyridoxamine; Figure 4 [albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113
    Complete structured claim and evidence

  2. Polarized Caco-2 cells supplied apically with PN generated PL and released more PL basolaterally than apically.

    Pyridoxine → Pyridoxal source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Results: Incubation with pyridoxine; Figure 4
    experimental_model
    Polarized human Caco-2 monolayers; human intestinal lysates.
    exposure
    100 or 1000 nM PN; 6-48 h.
    limitations
    Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Enterocytes can process a precursor before releasing pyridoxal.
    primary_references
    [albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113
    tissue_or_cell_type
    Polarized Caco-2 monolayers

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 124–135

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Polarized human Caco-2 monolayers; human intestinal lysates. · source_derived_draft · unverified_draft

    ### b6-transport-enterocyte-pn-to-pl Polarized Caco-2 cells supplied apically with PN generated PL and released more PL basolaterally than apically. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Enterocytes can process a precursor before releasing pyridoxal. organism: Homo sapiens tissue_or_cell_type: Polarized Caco-2 monolayers experimental_model: Polarized human Caco-2 monolayers; human intestinal lysates. limitations: Vitamer measurements establish net conversion; individual enzyme fluxes were not separately perturbed. exposure: 100 or 1000 nM PN; 6-48 h. evidence_location: Results: Incubation with pyridoxine; Figure 4 [albersen2013] The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model. (2013). https://pubmed.ncbi.nlm.nih.gov/23342087/ DOI: 10.1371/journal.pone.0054113
    Complete structured claim and evidence

  3. Forty-eight-hour PDXP siRNA restored PLP toward control concentrations in PLPBP-deficient HEK293 cells and decreased PL.

    Human PDXP knockdown → PLP source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_location
    Figure 6B-C
    experimental_model
    Human patient skin fibroblasts and CRISPR PLPBP-null HEK293 cells.
    exposure
    15 nM siRNA; 48 h; standard PN-containing medium.
    limitations
    Cell experiment; does not prove a direct PLPBP-PDXP interaction.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    Reducing breakdown restored the cellular PLP pool.
    primary_references
    [ciapaite2023] Maintenance of cellular vitamin B6 levels and mitochondrial oxidative function depend on pyridoxal 5'-phosphate homeostasis protein. (2023). https://pubmed.ncbi.nlm.nih.gov/37451483/ DOI: 10.1016/j.jbc.2023.105047
    tissue_or_cell_type
    HEK293 cells
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 439–450

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human patient skin fibroblasts and CRISPR PLPBP-null HEK293 cells. · source_derived_draft · unverified_draft

    ### b6-transport-pdxp-silencing-plpbp-null Forty-eight-hour PDXP siRNA restored PLP toward control concentrations in PLPBP-deficient HEK293 cells and decreased PL. Condition category: machinery_impairment nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Reducing breakdown restored the cellular PLP pool. organism: Homo sapiens tissue_or_cell_type: HEK293 cells experimental_model: Human patient skin fibroblasts and CRISPR PLPBP-null HEK293 cells. limitations: Cell experiment; does not prove a direct PLPBP-PDXP interaction. exposure: 15 nM siRNA; 48 h; standard PN-containing medium. evidence_location: Figure 6B-C [ciapaite2023] Maintenance of cellular vitamin B6 levels and mitochondrial oxidative function depend on pyridoxal 5'-phosphate homeostasis protein. (2023). https://pubmed.ncbi.nlm.nih.gov/37451483/ DOI: 10.1016/j.jbc.2023.105047
    Complete structured claim and evidence

In the sources

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

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