Question

Sucrase is a digestive enzyme that catalyzes the hydrolysis of the disaccharide sucrose into glucose and fructose. why can't lactose, a disaccharide composed of glucose and galactose, be hydrolyzed by sucrase?

Answer 1

Every enzymes are specific target

Answer 2

Sucrose binds to the active site on sucrase, and this puts stress on the bond between the 2 sugars that make up sucrose. The bond breaks, releasing glucose and fructose. But this active site won't accept lactose a disaccharide of different structure.