Xanthurenic acid is produced in
In the metabolism of Tryptophan, Kynurenin is an intermediate step. The accumulated Kynurenine is shunted to Xanthurenic acid. So, in pyridoxal deficiency, Xanthurenic acid is excreted in the urine.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 240
Tyrosine metabolism
Tryptophan metabolism
Cysteine metabolism
Valine metabolism
Metabolism of protein and amino acid