brown pigmented

Edge evidence

• tyrosine catabolism produces homogentisic acid METPO:2000202

  Tyrosine catabolism can generate homogentisic acid.

  • DOI:10.1128/AEM.67.8.3463-3468.2001 homogentisic acid accumulates in the medium Supports HGA accumulation as upstream of brown pigment formation.
• 4-hydroxyphenylpyruvate dioxygenase catalyzes formation of homogentisic acid biolink:catalyzes

  HppD catalyzes formation of homogentisic acid in pyomelanin pathways.

  • DOI:10.1371/journal.pone.0120923 catalyzes the reaction from 4-hydroxyphenylpyruvate to HGA Supports HppD-mediated HGA formation in bacterial pyomelanin production.
• homogentisic acid polymerizes to pyomelanin

  HGA oxidizes and polymerizes into pyomelanin.

  • DOI:10.1128/AEM.67.8.3463-3468.2001 spontaneously oxidize and polymerize Supports HGA polymerization as the source of pyomelanin.
• pyomelanin causes visible brown color biolink:causes

  Pyomelanin causes visible brown pigmentation.

  • DOI:10.1128/AEM.67.8.3463-3468.2001 Brown pigments are produced Supports brown color as the output of pyomelanin formation.
• visible brown color manifests as brown pigmented METPO:2007400

  Visible brown color manifests the brown-pigmented phenotype.

  • DOI:10.1016/j.biotechadv.2021.107773 black/brown color to the cells Supports brown microbial cell color as a melanin-related pigmentation phenotype.
• tyrosine catabolism produces 4-hydroxyphenylpyruvate METPO:2000202

  Tyrosine catabolism produces 4-hydroxyphenylpyruvate as an intermediate.

  • DOI:10.1038/s41564-023-01517-5 Tyrosine aminotransferases convert L-tyrosine into 4-hydroxyphenylpyruvate; biochemically generalizable precursor step.
• 4-hydroxyphenylpyruvate converted to homogentisic acid

  HppD converts 4-hydroxyphenylpyruvate to homogentisic acid.

  • DOI:10.1128/spectrum.00410-24 hppD codes for a protein responsible for conversion of 4-hydroxyphenylpyruvate to HGA.
• homogentisate 1,2-dioxygenase converts maleylacetoacetate

  HmgA converts homogentisic acid to maleylacetoacetate, the degradative branch.

  • DOI:10.1128/spectrum.00410-24 Homogentisate 1,2-dioxygenase (hmgA) converts HGA to maleylacetoacetate; core negative branch away from pigment formation.
• homogentisic acid auto-oxidizes to benzoquinoneacetic acid

  Excreted homogentisic acid spontaneously auto-oxidizes to benzoquinoneacetic acid.

  • DOI:10.1128/spectrum.00410-24 HGA is excreted and spontaneously auto-oxidizes to form benzoquinoneacetic acid.
• benzoquinoneacetic acid polymerizes to pyomelanin

  Benzoquinoneacetic acid self-polymerizes to produce pyomelanin.

  • DOI:10.1128/spectrum.00410-24 Auto-oxidation followed by self-polymerization to produce pyomelanin.