identifier: traitmech:000160
label: gamma-glutamyltransferase activity
definition: A physiological enzyme-activity phenotype in which a cell exhibits gamma-glutamyltransferase/glutathione-hydrolase
  activity, processing glutathione, glutathione-S-conjugates, or other N-terminal
  L-gamma-glutamyl substrates through a gamma-glutamyl-enzyme intermediate.
definition_source: https://iubmb.qmul.ac.uk/enzyme/EC3/4/19/13.html
trait_category: PHYSIOLOGY
term_kind: CLASS
mapping_status: PROPOSED
parent_traits:
- METPO:1000059
synonyms:
- synonym_text: gamma-glutamyl transferase
  synonym_type: RELATED_SYNONYM
  source: DOI:10.3389/fgene.2023.1240581
- synonym_text: gamma-glutamyl transpeptidase
  synonym_type: RELATED_SYNONYM
  source: https://iubmb.qmul.ac.uk/enzyme/EC3/4/19/13.html
- synonym_text: glutathione gamma-glutamate hydrolase
  synonym_type: RELATED_SYNONYM
  source: https://iubmb.qmul.ac.uk/enzyme/EC3/4/19/13.html
evidence:
- reference: https://iubmb.qmul.ac.uk/enzyme/EC3/4/19/13.html
  snippet: The enzyme binds its substrate by forming an initial γ-glutamyl-enzyme
    intermediate, releasing the <small>L</small>-cysteinylglycine part of the molecule.
    The enzyme then reacts with either a water molecule or a different acceptor substrate
    (usually an <small>L</small>-amino acid or a dipeptide) to form <small>L</small>-glutamate
    or a product containing a new &gamma;-glutamyl isopeptide bond, respectively.
    The enzyme acts on glutathione, glutathione-<i>S</i>-conjugates, and, at a lower
    level, on other substrates with an N-terminal <small>L</small>-&gamma;-glutamyl
    residue.
  notes: The NC-IUBMB EC 3.4.19.13 entry scopes the bifunctional glutathione gamma-glutamate
    hydrolase/gamma-glutamyltransferase enzyme across water- and acceptor-mediated
    reactions.
- reference: DOI:10.3389/fgene.2023.1240581
  snippet: Like Helicobacter canis, these two putative isolates are positive for oxidase,
    gamma-glutamyl transferase, and alkaline phosphatase and negative for catalase
    and urease activities.
  notes: Wang et al. detected gamma-glutamyltransferase activity in two Helicobacter
    zhangjianzhongii isolates with the API Campy biochemical panel.
- reference: DOI:10.3389/fgene.2023.1240581
  snippet: Both of these strains exhibit positive results for oxidase, gamma-glutamyl
    transferase, alkaline phosphatase, pyrrolidonyl arylamidase, L-arginine arylamidase,
    and L-aspartate arylamidase
  notes: The formal species description reports the same gamma-glutamyltransferase-positive
    phenotype in both H. zhangjianzhongii strains.
canonical_examples:
- taxon_id: NCBITaxon:2974574
  taxon_label: Helicobacter zhangjianzhongii
  note: Wang et al. reported both Helicobacter zhangjianzhongii isolates as positive
    for gamma-glutamyltransferase activity in the API Campy biochemical panel.
  reference: DOI:10.3389/fgene.2023.1240581
discussions:
- discussion_id: gamma-glutamyltransferase-activity-xref-gap
  prompt: Resolve an exact external ontology class for gamma-glutamyltransferase activity
    before adding a TraitRecord xref.
  kind: CURATION_TODO
  status: OPEN
  rationale: GO:0003840 gamma-glutamyltransferase activity is obsolete, and its replacement
    GO:0036374 glutathione hydrolase activity denotes a glutathione-hydrolysis molecular
    function rather than the organism-level gamma-glutamyltransferase/glutathione-hydrolase
    phenotype. GO:0036374 is appropriate as a causal-node grounding when a graph needs
    that hydrolysis half-reaction, not as an equivalent TraitRecord xref.
  posed_by: codex
  posed_date: '2026-09-12'
curation_history:
- timestamp: '2026-09-12T06:47:37Z'
  curator: codex
  action: MINTED_TRAITMECH_ID
  changes: Minted gamma-glutamyltransferase activity as a URL/DOI-backed TraitRecord
    after a repository-wide duplicate review covering ignored and hidden files; METPO
    has no exact gamma-glutamyltransferase activity class yet and the placeholder
    is reserved in proposals/metpo_traitmech_v37.
  llm_assisted: true