In the non-oxidative portion of the pentose phosphate pathway, 2-carbon fragments of keto-sugars can be transferred to other sugars to generate a larger sugar molecule. This reaction is catalyzed by which of the following enzymes?

(A) transketolase

(B) G6P dehydrogenase

(C) aldolase

(D) amilase

(A) Transketolase

Explanation:

Transketolase enzyme catalyzes the reaction in which a two-carbon fragment from a ketose donor is transferred to an aldose acceptor. The enzyme transfers the C-1 and C-2 of xylulose 5-phosphate (ketose) to ribose 5-phosphate (aldose).

The reaction results in formation of a seven-carbon product sedoheptulose 7-phosphate. The remaining part of xylulose is a three-carbon fragment and forms glyceraldehyde 3-phosphate.