Question

_____________ isomerizes α-D-glucopyranose to α-D –fructofuranose.

(a) Xylose isomerase

(b) Glucose isomerase

(c) Sucrose phosphorylase

(d) Invertase

The question was posed to me in an online quiz.

This intriguing question originated from High Fructose Corn Syrups and use of Immobilized Raffinase, Invertase and Lactase in division Immobilized Enzymes and their Uses of Enzyme Technology

Answer 1

Correct answer is (a) Xylose isomerase

The explanation is: The enzyme which isomerizes α-D-glucopyranose to α-D –fructofuranose is xylose isomerase. Whereas glucose isomerase isomerizes glucose to fructose. Sucrose phosphorylase converts fructose to sucrose releasing orthophosphate. Invertase catalyzes the hydrolysis of sucrose.