Answer to Question #248673 in Biochemistry for jah

Question

Why does cyclization of D-glucose give two isomers of α- and β-D-glucose?

Answer 1

The open chain form of glucose exists in small quantities and under physiological conditions glucose exists in a ring form. Due to cyclization of glucose molecule the C-1 carbonyl group reacts with C-5 hydroxyl group resulting in an intramolecular hemiacetal. Due to this hemiacetal formation glucose exists in α and β isomers.