Interactive amino acid metabolism map
Measured compounds are shown as clickable nodes. Module descriptions summarize representative reaction relationships; not every connecting intermediate is measured.
Pathway modules and biochemical relationships
Biological routes are simplified and distinguish measured analytes from supporting, unmeasured intermediates.
Urea cycle and aspartate nitrogen flow
Ornithine → citrulline → arginine → ornithine (intermediates omitted); aspartate supplies a nitrogen at the argininosuccinate step.
Serine, glycine and methyl transfers
Phosphoserine → serine ↔ glycine; sarcosine feeds glycine. Connections indicate multi-enzyme pathways.
Transsulfuration and redox
Methionine → homocysteine → cystathionine → cysteine. Homocystine is a redox dimer; cystine and GSSG are oxidized species.
Nitrogen and inhibitory neurotransmitter metabolism
Glutamine ↔ glutamate → GABA; glutamate also links to central carbon metabolism.
BCAA and related catabolites
Valine, leucine and isoleucine share early catabolic chemistry. β-Aminoisobutyrate has valine/thymine origins; α-aminobutyrate is not a BCAA.
Aromatic amino-acid metabolism
Phenylalanine → tyrosine. Tryptophan enters distinct kynurenine and serotonin routes.
Histidine-derived dipeptides and methylhistidines
Histidine is a building block for carnosine; anserine is a methylated dipeptide. Methylhistidines have multiple sources.
Connective-tissue markers and lysine catabolism
Hydroxyproline/hydroxylysine arise primarily through modification of protein-bound residues, rather than simple free-amino-acid reactions.
Serine- and ethanolamine-related phospholipids
Ethanolamine → phosphoethanolamine in phosphatidylethanolamine synthesis; phosphoserine is grouped with serine metabolism above.
Central carbon and nitrogen connections
Alanine exchanges nitrogen with pyruvate through transamination.
Creatine-related measurement
Creatinine is a creatine breakdown product with substantial renal-clearance dependence.
Interpretation note: a pathway grouping does not establish metabolic flux, enzyme activity, or tissue of origin. Sulfur redox pairs (cysteine/cystine, GSH/GSSG) are sensitive to pre-analytical handling. Hydroxyproline and hydroxylysine generally arise through protein-residue modification; homocystine is not free homocysteine.
Measured abundance is not equivalent to pathway flux. Interpret differences in the context of matrix, normalization, biological design, and analytical performance.