Carbohydrate Metabolism Special Pathways. Flashcards
Where does the HMS take place?
Cytosol
RBC, Skin, Adipose Tissue, Mammary Glands
Name the regulatory step of the PPP, including enzymes, products and reactants.
What are the regulators of this enzyme?
A deficiency of this enzyme, or reduced activity (favism) will cause what? Why?
G6P —G6PDH–> 6Phosphoglucono-lactone; NADPH
Regulators: (-), NADPH, fatty acyl CoA
Deficiency: Can cause hemolytic anemia in RBC. NADPH is used to prevent radical (damaging) oxidation in RBC’s
What is the name, and importance of the second dehydrogenase enzyme in the PPP? I am basically asking for the products..
It is a decarboxylase, produces CO2, and also produces the second NADPH
What is the final product of the oxidative PPP? what type of enzyme is responsible for the formation of this product?
Ribose-5-phosphate
Isomerase
Name (4) ways NADPH is utilized? Do the same (2) for ribose-5-phosphate
Reductive Biosynthesis of FA, Fighting reactive O2 species, Cytochrome P450, WBC function (phagocytosis) synthesis of NO (sm relaxer)
R5P: DNA/RNA synthesis, Nucleotide CoFactor function
What is the second Phase of the HMS?
Name (2) enzymes, and there purpose in sugar synthesis?
Do any need vitamin cofactors? If so name them
What are glycolysis intermediates produced by the PPP?
Sugar interconversion;
transketolases (B1(TTP), MG++)(+,- 2), transacetylases (+,-3c)
Fructose-6-phosphate, Glyceraldhyde-3-phosphate
What are outcomes 2, and 3 of the PPP, Stage II?
*the end produces recycled are Glycerol3P, and F6P
G6P, can be oxidized (breakdown) all the way COz creating: 12 NADPH
Glyceraldehyde –converted to> F6P
The PPP recycles products to make R5P for DNA/RNA
Summarize Glucose Fructose to Glucose interconversion
Fructose + ATP –Fructokinase–> F6P —Aldolase B–> DHAP (glycolysis) & Glyceraldehyde (converted to glycerol3P then to DHAP), DHAP –> Glucose
Summarize Galactose to Glucose interconversion
Galactose –galactoknase–> Gal6P + UDP-Glucose—GALT–> UDP-Gal6P + GlucoseP
Fructosuria
Fructose Intolerance
Galactocemia
What enzymes are deficient? What are the consequences? Why?
F: Fructokinase
FI: Aldolase B (spits F1P)
G: Galactokinase, and GALT.
High Circulation of ((P)) fructose and galactose. Big prob = no (P), Cataract formation. Caused by reversal of polyol pathway
Briefly explain polyol pathway
When glucose/fructose/galactose is high is circulation, the polyol pathway can reverse producing (sorbitol-alcohol).
Water follows sorbitol into cell and can cause swelling/lysis
What are (4) uses of glucuronic acid? What is a synthesis precursor?
Complex Carb synthesis (GAGS, polysaccharides) etc
Detoxification (binds makes things soluble)
Formation from glucose forms 1 NADH
precursor to L-absorbic acid (Vit C)
UDP-glucose
PPP in the following cells is mostly used for?
RBC? Liver/Mammary? Liver alone? Striated mm?
RBC: NADHP to reduce glutathione - protect membrane
L/M: NADHP needed for FA synthesis
L: P450
S; no PPP sorry
