Learn / Metabolism

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

Galactose metabolism (Leloir pathway) · Liver. 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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Galactose metabolism (Leloir pathway)

UDP-galactose

Made from Galactose-1-phosphate by Galactose-1-phosphate uridyltransferase (GALT) ★

Galactose-1-phosphate uridyltransferase (GALT) ★ rate-limiting — Galactose metabolism (Leloir pathway)

Deficiency: Classic galactosemia — Gal-1-P is toxic to liver, brain, kidney and lens: vomiting, jaundice, hepatomegaly, failure to thrive days after milk starts; E. coli sepsis; cataracts; intellectual disability. Remove ALL galactose/lactose

Gal-1-P + UDP-glucose → UDP-galactose + glucose-1-P. The critical step.

Condition cards:Galactosemia (GALT deficiency) →

Made from UDP-glucose by GALT (UDP-glucose donates the UDP)

GALT (UDP-glucose donates the UDP) — Galactose metabolism (Leloir pathway)

Becomes UDP-glucose via UDP-galactose 4-epimerase

UDP-galactose 4-epimerase — Galactose metabolism (Leloir pathway)

Reversible — also makes UDP-galactose for lactose, glycoproteins and glycolipids when there is no dietary galactose.