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une ch 29
pathways of sugar metabolism
Question | Answer |
---|---|
pentose phosphate pathway function | Functions: To make NADPH (used for detoxification [ie. glutathione synthesis] and Reductive Biosynthesis [ie. fatty acid synthesis]) and Ribose 5 phosphate (nucleotide synthesis) . |
pentose phosphate pathway s/p | Substrates: Glucose-6-phosphate and NADP+ Products: NADPH, CO2, ribose-5-phosphate, fructose-6-phosphate, and glyceraldehyde-3-phosphate |
ppp pathways | There are two routes the pathway can take, oxidative (irreversible) and nonoxidative (reversible). |
ppp oxidative pathway | The first pathway is the oxidative pathway. This is where NADPH, ribulose 5-phosphate, and CO2 are generated. This pathway is a substrate for glutathione reductase, fatty acid synthesis, cytochrome P450 monooxygenases, and deoxynucleotide synthesis. |
ppp nonoxidative pathway | The second pathway is the nonoxidative pathway. This pathway synthesizes ribose 5-phosphate. |
ppp s/p/c/r | Substrates: Glucose-6-phosphate and NADP+ Products: NADPH, CO2, ribose-5-phosphate, fructose-6-phosphate, and glyceraldehyde-3-phosphate Control Enzymes: Glucose-6-P dehydrogenase Regulation: Level of NADPH (product inhibition) (feedback inhibition) |
ppp feedback inhibition | Feedback inhibition: cells keep a high level of NADPH to push reactions forward, when levels of NADPH are high, oxidative pathway is inhibited. When NADPH levels are low, oxidative pathway is activated. |
ppp compartment/tissues of interest | Compartment(s): Cytosol Tissues of interest: Every cell in the body |