Component

Human sulfotransferase 1A1 / SULT1A1

Human sulfotransferase 1A1 / SULT1A1. Species, exposure and limitations are retained in each linked claim.

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. SULT1A1 had the strongest tested sulfating activity toward 6-hydroxymelatonin.

    Human sulfotransferase 1A1 / SULT1A1 → 6-Sulfatoxymelatonin / aMT6s source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/melatonin-research/26577053.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ab887dc7012d5f393de52ecf842b67282d51b61bac705b9ab187c1a3e24331d5", "start_char": 0, "end_char": 1378, "text_sha256": "ab887dc7012d5f393de52ecf842b67282d51b61bac705b9ab187c1a3e24331d5"}
    experimental_model
    Thirteen human SULT enzymes, labeled cells and tissue cytosols
    exposure
    6-hydroxymelatonin and N-acetylserotonin substrates; sulfate metabolic labeling
    limitations
    Enzyme ranking applies to tested conditions. Sulfation is a separate step from P450 hydroxylation; no dietary sulfur threshold was established.
    nutrient_topic
    Melatonin research collection; topical membership is not evidence of a direct dietary effect. · Melatonin
    organism
    Human recombinant enzymes, HepG2 and Caco-2 cells
    plain_language
    The hydroxylated metabolite undergoes another reaction before common urinary measurement.
    primary_references
    [melatonin-p26577053] Sulfation of 6-hydroxymelatonin, N-acetylserotonin and 4-hydroxyramelteon by the human cytosolic sulfotransferases (SULTs). (2016). https://pubmed.ncbi.nlm.nih.gov/26577053/ DOI: 10.3109/00498254.2015.1107656
    tissue_or_cell_type
    Sulfate conjugation

    Melatonin: synthesis, receptors, circadian timing and nutrient interactions (2026-09-17) · lines 630–641

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Thirteen human SULT enzymes, labeled cells and tissue cytosols · source_derived_draft · unverified_draft

    ### melatonin-sult1a1 SULT1A1 had the strongest tested sulfating activity toward 6-hydroxymelatonin. Condition category: normal nutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The hydroxylated metabolite undergoes another reaction before common urinary measurement. organism: Human recombinant enzymes, HepG2 and Caco-2 cells tissue_or_cell_type: Sulfate conjugation experimental_model: Thirteen human SULT enzymes, labeled cells and tissue cytosols limitations: Enzyme ranking applies to tested conditions. Sulfation is a separate step from P450 hydroxylation; no dietary sulfur threshold was established. exposure: 6-hydroxymelatonin and N-acetylserotonin substrates; sulfate metabolic labeling evidence_span: {"source_cache": "artifacts/melatonin-research/26577053.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ab887dc7012d5f393de52ecf842b67282d51b61bac705b9ab187c1a3e24331d5", "start_char": 0, "end_char": 1378, "text_sha256": "ab887dc7012d5f393de52ecf842b67282d51b61bac705b9ab187c1a3e24331d5"} [melatonin-p26577053] Sulfation of 6-hydroxymelatonin, N-acetylserotonin and 4-hydroxyramelteon by the human cytosolic sulfotransferases (SULTs). (2016). https://pubmed.ncbi.nlm.nih.gov/26577053/ DOI: 10.3109/00498254.2015.1107656
    Complete structured claim and evidence

  2. Human SULT1A1 catalyzed curcumin sulfation.

    Human sulfotransferase 1A1 / SULT1A1 → Curcumin sulfate source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/curcumin-research/11815407.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "028fbc6d7e7e728f7e52970df07c8e9b04053abe4799669798d593369d2c23b8", "start_char": 0, "end_char": 2113, "text_sha256": "028fbc6d7e7e728f7e52970df07c8e9b04053abe4799669798d593369d2c23b8"}
    experimental_model
    Human and rat tissue fractions and enzyme assays
    exposure
    Curcumin incubated with tissue fractions or purified sulfotransferases
    limitations
    Ex-vivo metabolism does not measure whole-person bioavailability. Isoforms are specified only where experimentally identified.
    nutrient_topic
    Curcumin research collection; topical membership is not evidence of a direct dietary effect. · Curcumin
    organism
    Human assays below; rat experiments not merged
    plain_language
    This enzyme adds a sulfate group to curcumin.
    primary_references
    [curcumin-p11815407] Metabolism of the cancer chemopreventive agent curcumin in human and rat intestine. (2002). https://pubmed.ncbi.nlm.nih.gov/11815407/
    tissue_or_cell_type
    Intestinal and hepatic microsomes and cytosol

    Curcumin: metabolism, signaling and nutrient connections (2026-09-17) · lines 112–123

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human and rat tissue fractions and enzyme assays · source_derived_draft · unverified_draft

    ### curcumin-sult1a1 Human SULT1A1 catalyzed curcumin sulfation. Condition category: normal nutrient_topic: Curcumin research collection; topical membership is not evidence of a direct dietary effect. plain_language: This enzyme adds a sulfate group to curcumin. organism: Human assays below; rat experiments not merged tissue_or_cell_type: Intestinal and hepatic microsomes and cytosol experimental_model: Human and rat tissue fractions and enzyme assays limitations: Ex-vivo metabolism does not measure whole-person bioavailability. Isoforms are specified only where experimentally identified. exposure: Curcumin incubated with tissue fractions or purified sulfotransferases evidence_span: {"source_cache": "artifacts/curcumin-research/11815407.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "028fbc6d7e7e728f7e52970df07c8e9b04053abe4799669798d593369d2c23b8", "start_char": 0, "end_char": 2113, "text_sha256": "028fbc6d7e7e728f7e52970df07c8e9b04053abe4799669798d593369d2c23b8"} [curcumin-p11815407] Metabolism of the cancer chemopreventive agent curcumin in human and rat intestine. (2002). https://pubmed.ncbi.nlm.nih.gov/11815407/
    Complete structured claim and evidence

  3. Recombinant human SULT1A1*2 converted indoxyl to indoxyl sulfate using PAPS; apparent indoxyl Km was 5.6 ± 1.8 micromolar.

    Human sulfotransferase 1A1 / SULT1A1 → Indoxyl sulfate source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human recombinant allozyme and liver cytosol kinetic comparison.
    limitations
    Sulfation does not necessarily make a retained metabolite harmless; no inference that sulfur intake controls clinical toxicity.
    nutrient_topic
    Tryptophan collection; molecular form, preparation, species, exposure and manipulation remain explicit. · L-Tryptophan
    plain_language
    A human sulfation enzyme adds a sulfur-containing group to the metabolite.
    primary_references
    Sulfation of indoxyl by human and rat aryl (phenol) sulfotransferases to form indoxyl sulfate. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12064372/ · DOI 10.1007/BF03190428

    Tryptophan: transport, protein synthesis, neuroactive metabolites, NAD and microbial pathways (2026-09-19) · lines 594–600

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human recombinant allozyme and liver cytosol kinetic comparison. · source_derived_draft · unverified_draft

    ## tryptophan-indoxyl-sulfation A human sulfation enzyme adds a sulfur-containing group to the metabolite. Recombinant human SULT1A1*2 converted indoxyl to indoxyl sulfate using PAPS; apparent indoxyl Km was 5.6 ± 1.8 micromolar. Model: Human recombinant allozyme and liver cytosol kinetic comparison. Limitations: Sulfation does not necessarily make a retained metabolite harmless; no inference that sulfur intake controls clinical toxicity. Evidence access: Primary abstract Sulfation of indoxyl by human and rat aryl (phenol) sulfotransferases to form indoxyl sulfate. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12064372/ · DOI 10.1007/BF03190428
    Complete structured claim and evidence

  4. The 2016 SULT1A1 allostery study explicitly reported that EGCG was not a SULT1A1 substrate but was sulfonated by SULT2A1.

    Human sulfotransferase 1A1 / SULT1A1 → Epigallocatechin-3-gallate (EGCG) source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Equilibrium binding and pre-steady-state human SULT enzyme experiments.
    limitations
    This differs from the later SULT1A1 assignment; assay and product-identification differences require comparison.
    nutrient_topic
    EGCG collection; comparator and shared-pathway records retain their actual intervention. · Epigallocatechin-3-gallate (EGCG)
    plain_language
    An earlier enzyme study gives a different substrate assignment.
    primary_references
    Isozyme Specific Allosteric Regulation of Human Sulfotransferase 1A1. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27356022/ · DOI 10.1021/acs.biochem.6b00401

    EGCG: receptor signaling, metabolism, nutrient interactions and discovery questions (2026-09-18) · lines 300–306

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Equilibrium binding and pre-steady-state human SULT enzyme experiments. · source_derived_draft · unverified_draft

    ## egcg-sult-not-substrate An earlier enzyme study gives a different substrate assignment. The 2016 SULT1A1 allostery study explicitly reported that EGCG was not a SULT1A1 substrate but was sulfonated by SULT2A1. Model: Equilibrium binding and pre-steady-state human SULT enzyme experiments. Limitations: This differs from the later SULT1A1 assignment; assay and product-identification differences require comparison. Evidence access: primary abstract. Isozyme Specific Allosteric Regulation of Human Sulfotransferase 1A1. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27356022/ · DOI 10.1021/acs.biochem.6b00401
    Complete structured claim and evidence

  5. The 2022 study assigned hepatic EGCG sulfation to SULT1A1.

    Human sulfotransferase 1A1 / SULT1A1 → Epigallocatechin-3-gallate (EGCG) source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Human liver/intestinal cytosol, enzyme assignment and a human ingestion pharmacokinetic study.
    limitations
    Formation rate and metabolite exposure do not prove identical biological effects of free and conjugated EGCG.
    nutrient_topic
    EGCG collection; comparator and shared-pathway records retain their actual intervention. · Epigallocatechin-3-gallate (EGCG)
    plain_language
    One study identifies this enzyme as a route for processing EGCG.
    primary_references
    4″-Sulfation Is the Major Metabolic Pathway of Epigallocatechin-3-gallate in Humans: Characterization of Metabolites, Enzymatic Analysis, and Pharmacokinetic Profiling. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35786898/ · DOI 10.1021/acs.jafc.2c02150

    EGCG: receptor signaling, metabolism, nutrient interactions and discovery questions (2026-09-18) · lines 276–282

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human liver/intestinal cytosol, enzyme assignment and a human ingestion pharmacokinetic study. · source_derived_draft · unverified_draft

    ## egcg-sult1a1-substrate One study identifies this enzyme as a route for processing EGCG. The 2022 study assigned hepatic EGCG sulfation to SULT1A1. Model: Human liver/intestinal cytosol, enzyme assignment and a human ingestion pharmacokinetic study. Limitations: Formation rate and metabolite exposure do not prove identical biological effects of free and conjugated EGCG. Evidence access: primary abstract. 4″-Sulfation Is the Major Metabolic Pathway of Epigallocatechin-3-gallate in Humans: Characterization of Metabolites, Enzymatic Analysis, and Pharmacokinetic Profiling. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35786898/ · DOI 10.1021/acs.jafc.2c02150
    Complete structured claim and evidence

What acts on it

  1. EGCG stabilized the closed SULT1A1 active-site cap, slowed nucleotide release and inhibited turnover; nucleotide-bound enzyme showed 17-fold tighter EGCG binding.

    Epigallocatechin-3-gallate (EGCG) → Human sulfotransferase 1A1 / SULT1A1 source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Allosteric binding/kinetic model; weak active-site binding also observed.
    limitations
    Substrate status and inhibition are separate questions; not proof of altered melatonin or hormone levels in people.
    nutrient_topic
    EGCG collection; comparator and shared-pathway records retain their actual intervention. · Epigallocatechin-3-gallate (EGCG)
    plain_language
    EGCG can trap this enzyme in a slower-cycling state.
    primary_references
    Isozyme Specific Allosteric Regulation of Human Sulfotransferase 1A1. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27356022/ · DOI 10.1021/acs.biochem.6b00401

    EGCG: receptor signaling, metabolism, nutrient interactions and discovery questions (2026-09-18) · lines 308–314

    AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Allosteric binding/kinetic model; weak active-site binding also observed. · source_derived_draft · unverified_draft

    ## egcg-sult-cap EGCG can trap this enzyme in a slower-cycling state. EGCG stabilized the closed SULT1A1 active-site cap, slowed nucleotide release and inhibited turnover; nucleotide-bound enzyme showed 17-fold tighter EGCG binding. Model: Allosteric binding/kinetic model; weak active-site binding also observed. Limitations: Substrate status and inhibition are separate questions; not proof of altered melatonin or hormone levels in people. Evidence access: primary abstract. Isozyme Specific Allosteric Regulation of Human Sulfotransferase 1A1. · 2016 · https://pubmed.ncbi.nlm.nih.gov/27356022/ · DOI 10.1021/acs.biochem.6b00401
    Complete structured claim and evidence

In the sources

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