Tyrosine

amino-acid · endocrine · integumentary · Oral

Tyrosine, an amino acid. Catecholamine pathway: Tyr → L-DOPA (tyrosine hydroxylase, rate-limiting; see catecholamine synthesis) → dopamine (AADC) → norepinephrine…

Catecholamine pathway: Tyr → L-DOPA (tyrosine hydroxylase, rate-limiting; see Catecholamine synthesis) → Dopamine (AADC) → Norepinephrine (DβH) → epinephrine (PNMT). Also substrate for thyroid hormone (T3/T4 is iodinated tyrosine) and melanin (via tyrosinase). Phosphorylation site (tyrosine kinase family).

Melamed 1980 (PMID:7190187) reports the supplemental effect as a ratio rather than a concentration — "the plasma tyrosine ratio increased from 0.13 to 0.21" — which is the quantity brain uptake actually depends on. Sampling in the cited dose-response study (PMID:29168741) stopped at 240 min, too short to support any terminal half-life.

Related compounds

• Levodopa — synergistic
• Dopamine — synergistic

Sources: PMID:10837313, PMID:29168741, PMID:7190187, PMID:6538743