Component

Human MPST active-site cysteine persulfide

Context-specific entity; species, compartment and exposure are stated on each claim.

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

Where it participates (unsigned role)

  1. Human MPST supported H2S production with thioredoxin and several low-molecular-weight acceptors, including cysteine, glutathione and dihydrolipoic acid.

    Human mercaptopyruvate sulfurtransferase / MPST → Thiol acceptors in purified human MPST assays source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract and primary figure descriptions
    experimental_model
    Purified human MPST kinetics; concentrations and acceptors varied.
    limitations
    Some small-thiol assays used millimolar concentrations; these are not demonstrated effects of oral cysteine or lipoic acid.
    nutrient_topic
    L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Cysteine
    plain_language
    Sharing a sulfur-transfer route does not make these acceptors equally effective inside cells.
    primary_references
    Structure and kinetic analysis of H2S production by human mercaptopyruvate sulfurtransferase. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23698001/ · DOI 10.1074/jbc.M113.466177

    L-Cysteine: sulfur allocation, redox supply and cross-nutrient mechanisms (2026-09-19) · lines 460–466

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified human MPST kinetics; concentrations and acceptors varied. · source_derived_draft · unverified_draft

    ## l-cysteine-mpst-acceptor-choice Sharing a sulfur-transfer route does not make these acceptors equally effective inside cells. Human MPST supported H2S production with thioredoxin and several low-molecular-weight acceptors, including cysteine, glutathione and dihydrolipoic acid. Model: Purified human MPST kinetics; concentrations and acceptors varied. Limitations: Some small-thiol assays used millimolar concentrations; these are not demonstrated effects of oral cysteine or lipoic acid. Evidence access: Primary abstract and primary figure descriptions Structure and kinetic analysis of H2S production by human mercaptopyruvate sulfurtransferase. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23698001/ · DOI 10.1074/jbc.M113.466177
    Complete structured claim and evidence

  2. N-acetylcysteine was a poor MPST sulfur acceptor in the reported kinetic experiments.

    N-Acetyl-L-cysteine → Human mercaptopyruvate sulfurtransferase / MPST source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Recombinant human MPST assays.
    limitations
    This does not negate NAC metabolism to cysteine or its other mechanisms.
    nutrient_topic
    L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Cysteine
    plain_language
    A cysteine precursor does not necessarily substitute for cysteine in each chemical reaction.
    primary_references
    Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32179647/ · DOI 10.1074/jbc.RA120.012616

    L-Cysteine: sulfur allocation, redox supply and cross-nutrient mechanisms (2026-09-19) · lines 476–482

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Recombinant human MPST assays. · source_derived_draft · unverified_draft

    ## l-cysteine-mpst-nac-distinction A cysteine precursor does not necessarily substitute for cysteine in each chemical reaction. N-acetylcysteine was a poor MPST sulfur acceptor in the reported kinetic experiments. Model: Recombinant human MPST assays. Limitations: This does not negate NAC metabolism to cysteine or its other mechanisms. Evidence access: Primary abstract Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32179647/ · DOI 10.1074/jbc.RA120.012616
    Complete structured claim and evidence

  3. Human MPST transfers sulfur from 3-mercaptopyruvate to its active-site Cys248, releasing pyruvate and forming an enzyme-bound persulfide.

    Human mercaptopyruvate sulfurtransferase / MPST → 3-Mercaptopyruvate source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract and primary figure descriptions
    experimental_model
    Purified human MPST structure and kinetics at pH 7.4.
    limitations
    The upstream cysteine transamination is pathway context; this experiment does not identify its dominant human tissue isoenzyme.
    nutrient_topic
    L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Cysteine
    plain_language
    A cysteine-derived intermediate hands sulfur to an enzyme before it reaches another acceptor.
    primary_references
    Structure and kinetic analysis of H2S production by human mercaptopyruvate sulfurtransferase. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23698001/ · DOI 10.1074/jbc.M113.466177

    L-Cysteine: sulfur allocation, redox supply and cross-nutrient mechanisms (2026-09-19) · lines 452–458

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified human MPST structure and kinetics at pH 7.4. · source_derived_draft · unverified_draft

    ## l-cysteine-mpst-sulfur-transfer A cysteine-derived intermediate hands sulfur to an enzyme before it reaches another acceptor. Human MPST transfers sulfur from 3-mercaptopyruvate to its active-site Cys248, releasing pyruvate and forming an enzyme-bound persulfide. Model: Purified human MPST structure and kinetics at pH 7.4. Limitations: The upstream cysteine transamination is pathway context; this experiment does not identify its dominant human tissue isoenzyme. Evidence access: Primary abstract and primary figure descriptions Structure and kinetic analysis of H2S production by human mercaptopyruvate sulfurtransferase. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23698001/ · DOI 10.1074/jbc.M113.466177
    Complete structured claim and evidence

  4. Thioredoxin showed substrate inhibition in human MPST assays and increased the apparent Km for 3-mercaptopyruvate relative to other acceptors.

    Thioredoxin / TXN → Human mercaptopyruvate sulfurtransferase / MPST source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Recombinant human MPST isoform kinetics.
    limitations
    Predicted tissue sulfur allocation was based on simulations; no human dietary response was measured.
    nutrient_topic
    L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Cysteine
    plain_language
    More of a redox partner did not simply produce a faster reaction.
    primary_references
    Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32179647/ · DOI 10.1074/jbc.RA120.012616

    L-Cysteine: sulfur allocation, redox supply and cross-nutrient mechanisms (2026-09-19) · lines 468–474

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Recombinant human MPST isoform kinetics. · source_derived_draft · unverified_draft

    ## l-cysteine-mpst-thioredoxin-inhibition More of a redox partner did not simply produce a faster reaction. Thioredoxin showed substrate inhibition in human MPST assays and increased the apparent Km for 3-mercaptopyruvate relative to other acceptors. Model: Recombinant human MPST isoform kinetics. Limitations: Predicted tissue sulfur allocation was based on simulations; no human dietary response was measured. Evidence access: Primary abstract Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations. · 2020 · https://pubmed.ncbi.nlm.nih.gov/32179647/ · DOI 10.1074/jbc.RA120.012616
    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