Biosynthesis of carbohydrate

• Glucose is the only precursor of lactose.
• Two molecules of glucose must enter the secretary cell for each molecule of lactose formed.
• One of the glucose units converted to form galactose.
• An enzyme, lactose synthetage, catalyses the condensation of the second glucose molecule with galactose.
• This enzyme is composed of two sub units one of these sub units is α lactalbumin, a major protein component of milk.