Question

give the 3 dimensional structure of the hexokinase enzyme.

Answer 1

The International Union of Biochemistry has classified enzymes into 6 types-

Class I- Oxidoreductases

Class II- Transferases

Class III- Hydrolases

Class IV- Lyases

Class V- Isomerases

Class VI- Ligases

Hexokinases belong to the Class II enzymes- Transferases in view that it phosphorylates a hexose molecule (a carbohydrate with 6 carbon atoms) into hexose-6-phosphate. This enzyme plays a very important role in glycolysis because it converts glucose molecule into glucose-6-phosphate. Hexokinase has various isozymes- Hexokinase A, B, C, D. Hexokinase D is also called as Glucokinase which has a high saturation point for glucose molecule.

The structure of Hexokinase consists of both α and β sheets. The ATP-binding domain comprises of 3 α-helices and 5 β-sheets. Out of these 5 β-sheets, one is anti-parallel to the other 4 β-sheets. The molecular weight of hexokinase is nearly 100 kD.

A representation of the enzyme Hexokinase is given below.