BIOL 540 Study Guide - Quiz Guide: Pentose Phosphate Pathway, Glutathione Reductase, Oxidative Decarboxylation
Document Summary
There are two stages for pentose phosphate pathway: Oxidative decarboxylation (irreversible): removes carbon dioxide and leaves a reducing equivalence. Nadph: single carbon has 4 high energy electrons available, and 2 carbons are oxidized giving 8 total electrons. Nonoxidative phase: recycles ribulose-5-phosphate to glycolytic intermediates and reactions are freely reversible. Substrate: ribulose 5-phosphate ( , ribulose 5-phosphate ( ) Or: ribose 5-phosphate (-2c, xylulose 5-phoshate (+2c, glyceraldehyde 3-phosphate (+3c, sedoheptulose 7-phosphate (-3c) Transketolase: xylulose 5-phosphate (-2c, erythrose 4-phosphate (+2c) product, ribose 5-phosphate, xylulose 5-phosphate ( , glyceraldehyde 3-phosphate, sedoheptulose 7-phosphate, fructose 6-phosphate (leaves, erythrose 4-phosphate, glyceraldehyde 3-phosphate, fructose 6-phosphate. 3 ribulose 5-phosphate 2 fructose 6-phosphate + glyceraldehyde 3-phosphate. Metabolic demands control the production of nadph and sugar intermediates. Low demand for ribose 5-phosphate and no demands for nadph: reaction of non-oxidation pentose phosphate pathway produces glycolytic intermediates (undergoes stage 2) and can then undergo glycolysis, makes more fats (requires nadph)
