The non-oxidative phase generates ribose precursors
The non-oxidative phase of the pathway, including the following reactions, converts pentose-5-phosphate to other sugars.
i) Ribulose-5-phosphate is acted on by ribulose-5-phosphate epimerase, which changes the configuration at carbon 3 fonning xylulose-5- phosphate, and also by the enzyme ribose-5-phosphate ketoisomerase, which converts ribulose-5-phosphate to ribose-5-phosphate.
ii) The next step involves the action of the enzyme transketolase. Transketolase with the help of TDP and Mg++ transfers carbons land 2 of xylulose-5-phosphate to ribose-5-phosphate forming sedoheptulose-7-phosphate and glyceraldehyde-3-phosphate