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Metabolic pathways

Every FMK pathway as a clickable map. Pick one pathway to hammer it — next step, enzyme, regulator, cofactor, and the facts that get tested (NADPH and who needs it, rate-limiting steps, deficiencies) — or set it to all pathways for a mixed drill. Every answer says which enzyme and which pathway.

Pathway

Catecholamines, serotonin & the tyrosine tree · CNS and sympathetic ganglia (dopamine, NE); adrenal medulla only for epinephrine; melanocytes for melanin; liver for the degradation arm; serotonin in CNS raphe nuclei, gut enterochromaffin cells and platelets, with melatonin made from it in the pineal. Enzymes sit beside the arrows, ★ = rate-limiting, ⊕/⊖ = activators/inhibitors (toggle), −ATP +NADH = what the step spends and makes (toggle ⚡), dashed = allosteric signal, shaded bands = compartment. Drag to pan.

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Catecholamines, serotonin & the tyrosine tree

Fumarate + acetoacetate → TCA cycle

Made from Fumarylacetoacetate by Fumarylacetoacetate hydrolase

Fumarylacetoacetate hydrolase · irreversible — Catecholamines, serotonin & the tyrosine tree

Deficiency: TYROSINEMIA TYPE I — fumarylacetoacetate and succinylacetone accumulate and are hepatotoxic and nephrotoxic: liver failure, renal Fanconi syndrome, cabbage-like odour. Treated with nitisinone, which blocks the pathway two steps upstream

The end of the line: fumarate (glucogenic) plus acetoacetate (ketogenic) — so tyrosine is BOTH.

Condition cards:Tyrosinemia type I →