09 Fructose And Galactose
Absorption
monosaccharides
Fructose
table sugar
fructose can be metabolized and feed into glycolysis
fructokinase add phosphate from ATP
aldolase B splits F1P to 2 3C molecules
fructose enter pathway beyond rate limiting step, faster than either glucose/galactose
hexokinase can convert fructose to F6P (step 2)
Essential Fructosuria
Hereditary Fructose Intolerance
no aldolase
fructose continuously converted to F1P, using up ATP
need ATP for gluconeogenesis and glycogen breakdown
no fructose from breast milk
wean from breast milk, start fructose
Polyol
sorbitol converted to fructose
diabetes locaitons
Galactose
G1P intermediate in glycogen synthesis, can be used for glycogen synthesis or converted to G6P
Classic Galactosemia
GALT
G1P builds up in liver and leads to liver damage, also deplete ATP supply
also causes cataracts
galactose in milk
Galactokinase Deficiency
Galactose not converted to G1P, milder symptoms, no depletion of phosphate and no trapping in liver
young child with vision problems
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