Other Carbohydrates Flashcards
why is NADPH important
It is important for the synthesis of reducing equivlents, NADPH, for glutathione (GSH) reduction
what is the first step of the pentose phosphate pathway?
G6P is converted into 6 phosphoglucono alpha lactone using Glucose-6- dehydrogenase
What occurs when you have a deficiency in G6P dehydrogenase
you do not get the PPP and have no NADPH made to protect the cell
G6P dehydrogenase
Converts G6P to 6 phosphoglucono delta lactone
most common deficincy - cannot make NADPH
X-linked
jaundice
get hemolytic anemia due to the increased ROS. Will see heinz bodies
What are the names of the enzymes that transfer carbons in the PPP
transketolase and transaldolase
what is the enzyme that uses Thiamine as a cofactor?
transketolase
Where is the second NADPH of the PPP generated?
between 6-phospho gluconate and ribulose 5P. It uses the 6-phosphogluconate dehydrogenase enzyme. It is a decarboxylation rxn.
6 phospho gluconate dehydrogenase
gain an NADPH in the PPP by convering 6 phosphpo gluconate to ribulose 5P
Fructose Metabolism takes place
in the liver
what is the rate limiting step of fructose breadown?
Aldolase B, converion of F1P to glycerol and DHAP
between F1P and F16BP which is preferntially cleaved by aldolase B?
F16BP
path way of fructose break down?
Fructose becomes F1P using fructokinase or F6P using hexokinase.F6P is broken down into F16BP using Phosphofructokinase. Using aldolase B, F1P is broken down into DHAP and Glyceraldehyde and F16BP is borken into DHAP and G3P
essential fructosuria
not bad. When you have a defect in
action of phosphofructokinase
convert F6P to F16BP
deficiency of psosphofructokinase
essential frucosuria
deficiency in aldolase B
hereditary fructose intolerence.
hereditary fructose intolerance
deficiency in aldolase B. Trap phosphate stores in F1P, which stops OxPhos –> liver failure.
where does sorbitol come from?
It comes from the break down of glucose via aldol reductase. Occurs during hyperglycemia - glucose takes this alternative pathway. capacity of hexokinase is exceeded
what does sorbitol do?
diabetic neuropathy!
how do you get fructose from glucose?
convert to sorbitol, convert sorbitol to fructose.
why do we need to make fructose?
so the spermies can swim! Sperm use fruotse for major fuel source
Classic Galactasemia
When you have a problem with the Gal 1-P urididyl transferase which converts Gal-1-p to Glu 1P
pathway of making Lactose
G1p –> UDP Glu–> UDP Gal –> Lactose.
what enzyme converts UDP Gal –> Lactose
lactose synthase
