Question

The reversible interconversion reactions of the pentose phosphate pathway can operate either to converi Map pentoses to hexoses (when operating in an oxidative mode to generate NADPH) or to convert hexoses to pentoses (when operating in a non-oxidative mode to generate pentoses for nucleic acid synthesis). Two key enzymes in these interconversion reactions are transaldolase and transketolase, and a key intermediate is the seven-carbon sugar sedoheptulose-7-phosphate. Identify the products formed from sedoheptulose-7-phosphate and glyceraldehyde-3-phosphate with each of these enzymes.

Answer 1

Answer 2

• Sedoheptulose-7-phopshate reacts with glyceraldehyde three phosphate in the presence of trnasaldolase to give, erythrose 4-phosphate + fructose 6-phosphate.
• Sedoheptulose-7-phopshate reacts with glyceraldehyde three phosphate in the presence of trnasketolase to give, xylulose -5- phosphate and ribose-5-phosphate.