Component

Human PLP-binding protein / PLPBP

Human PLP homeostasis protein, formerly PROSC.

4 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. Mass spectrometry of reduced recombinant human PLPBP identified Lys47 as the PLP-binding residue; spectroscopy supported an internal aldimine.

    Human PLP-binding protein / PLPBP → PLP source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Figure 1C-D
    experimental_model
    Recombinant human PLPBP and HEK293 proteomics.
    exposure
    NaBH4 reduction, LC-MS/MS and spectral analysis.
    limitations
    Binding alone does not prove direct cofactor delivery to target enzymes.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    PLPBP physically binds PLP through a lysine residue.
    primary_references
    [fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857
    tissue_or_cell_type
    Recombinant human protein

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 387–398

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human PLPBP and HEK293 proteomics. · source_derived_draft · unverified_draft

    ### b6-transport-plpbp-binding Mass spectrometry of reduced recombinant human PLPBP identified Lys47 as the PLP-binding residue; spectroscopy supported an internal aldimine. Condition category: normal nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: PLPBP physically binds PLP through a lysine residue. organism: Homo sapiens tissue_or_cell_type: Recombinant human protein experimental_model: Recombinant human PLPBP and HEK293 proteomics. limitations: Binding alone does not prove direct cofactor delivery to target enzymes. exposure: NaBH4 reduction, LC-MS/MS and spectral analysis. evidence_location: Figure 1C-D [fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. PLPBP-deficient patient fibroblasts in Darin 2016 accumulated approximately two- to threefold more PLP than controls in the tested culture medium.

    Human biallelic PLPBP impairment → PLP source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_location
    Indexed abstract; full-text discussion of cultured patient fibroblasts
    experimental_model
    Patient fibroblasts and biochemical studies in vitamin-B6-dependent epilepsy.
    exposure
    Patient cells cultured in normal medium containing serum and pyridoxine.
    limitations
    Later different cultures showed lower PLP; bulk PLP is not enzyme-specific cofactor availability.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    A cellular handling defect can raise the measured PLP pool.
    primary_references
    [darin2016] Mutations in PROSC Disrupt Cellular Pyridoxal Phosphate Homeostasis and Cause Vitamin-B6-Dependent Epilepsy. (2016). https://pubmed.ncbi.nlm.nih.gov/27912044/ DOI: 10.1016/j.ajhg.2016.10.011
    tissue_or_cell_type
    Patient skin fibroblasts
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 413–424

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Patient fibroblasts and biochemical studies in vitamin-B6-dependent epilepsy. · source_derived_draft · unverified_draft

    ### b6-transport-plpbp-fibroblast-accumulation PLPBP-deficient patient fibroblasts in Darin 2016 accumulated approximately two- to threefold more PLP than controls in the tested culture medium. Condition category: machinery_impairment nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A cellular handling defect can raise the measured PLP pool. organism: Homo sapiens tissue_or_cell_type: Patient skin fibroblasts experimental_model: Patient fibroblasts and biochemical studies in vitamin-B6-dependent epilepsy. limitations: Later different cultures showed lower PLP; bulk PLP is not enzyme-specific cofactor availability. exposure: Patient cells cultured in normal medium containing serum and pyridoxine. evidence_location: Indexed abstract; full-text discussion of cultured patient fibroblasts [darin2016] Mutations in PROSC Disrupt Cellular Pyridoxal Phosphate Homeostasis and Cause Vitamin-B6-Dependent Epilepsy. (2016). https://pubmed.ncbi.nlm.nih.gov/27912044/ DOI: 10.1016/j.ajhg.2016.10.011
    Complete structured claim and evidence

  2. In the 2023 study, PLP was lower in PLPBP-deficient fibroblasts and HEK293 cells after 96 hours with 20 micromolar PN, PM or PL.

    Human PLPBP knockout genotype → PLP source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_location
    Figure 2A-B; Discussion
    experimental_model
    Human patient skin fibroblasts and CRISPR PLPBP-null HEK293 cells.
    exposure
    20 micromolar individual vitamer for 96 h.
    limitations
    Different conditions may explain the earlier accumulation result.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    The pool response depended on the cell model and culture conditions.
    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
    Skin fibroblasts and HEK293 cells
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 426–437

    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-plpbp-low-plp In the 2023 study, PLP was lower in PLPBP-deficient fibroblasts and HEK293 cells after 96 hours with 20 micromolar PN, PM or PL. Condition category: machinery_impairment nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The pool response depended on the cell model and culture conditions. organism: Homo sapiens tissue_or_cell_type: Skin fibroblasts and HEK293 cells experimental_model: Human patient skin fibroblasts and CRISPR PLPBP-null HEK293 cells. limitations: Different conditions may explain the earlier accumulation result. exposure: 20 micromolar individual vitamer for 96 h. evidence_location: Figure 2A-B; Discussion [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

  3. Purified R241Q lacked detectable bound PLP, but a fourfold molar PLP excess produced a mixture including holo-protein.

    Human PLPBP Arg241Gln → PLP source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_location
    Full text: biochemical properties and Figure 2B-D
    experimental_model
    Recombinant human PLPBP and HEK293 proteomics.
    exposure
    Purification followed by PLP addition.
    limitations
    Biochemical reconstitution does not establish clinical rescue.
    nutrient_topic
    Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B6
    organism
    Homo sapiens
    plain_language
    This variant binds poorly but is not absolutely incapable of binding.
    primary_references
    [fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857
    tissue_or_cell_type
    Recombinant human protein
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin B6: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 400–411

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recombinant human PLPBP and HEK293 proteomics. · source_derived_draft · unverified_draft

    ### b6-transport-plpbp-r241q Purified R241Q lacked detectable bound PLP, but a fourfold molar PLP excess produced a mixture including holo-protein. Condition category: machinery_impairment nutrient_topic: Vitamin B6 research collection; topical membership is not evidence of a direct dietary effect. plain_language: This variant binds poorly but is not absolutely incapable of binding. organism: Homo sapiens tissue_or_cell_type: Recombinant human protein experimental_model: Recombinant human PLPBP and HEK293 proteomics. limitations: Biochemical reconstitution does not establish clinical rescue. exposure: Purification followed by PLP addition. evidence_location: Full text: biochemical properties and Figure 2B-D [fux2020] Biochemical and Proteomic Studies of Human Pyridoxal 5'-Phosphate-Binding Protein (PLPBP). (2020). https://pubmed.ncbi.nlm.nih.gov/31825581/ DOI: 10.1021/acschembio.9b00857
    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.

    Evidence, AI assistance and curation standards