Other important amino acid derivatives

Trp → melatonin

Phe and Tyr → thyroid hormones, melanin

Gly → heme, purines, creatine, conjugation with bile acids

Arg and Ornithine → creatine, polyamines (spermidine, spermine)

Gly, Glu, Asp → purines and pyrimidines

Cys → taurine