Category: catabolism
Hepatic-dominant fructose handling, distinct from glycolysis. Fructose → fructose-1-P (fructokinase / ketohexokinase, KHK — bypasses the insulin-sensitive PFK-1 step). F1P → glyceraldehyde + DHAP (aldolase B). Glyceraldehyde → glyceraldehyde-3-P (triokinase) → glycolysis. Bypass of PFK-1 makes fructose uniquely lipogenic at high intakes — drives hepatic de novo lipogenesis (see fatty_acid_biosynthesis) + NAFLD risk. Hereditary fructose intolerance = aldolase B deficiency (autosomal recessive): F1P accumulates, depletes ATP + phosphate, produces hypoglycemia + vomiting + hepatic injury after fructose / sucrose / sorbitol exposure. Essential fructosuria = benign fructokinase deficiency (no symptoms — fructose excreted unchanged).