Question

Hexokinase (Glucose + ATP ⟶ Glucose 6-P + ADP) belongs to the category
A. Transferases
B. Lyases
C. Oxidoreductases
D. Isomerases

Answer 1

Hexokinases are enzymes which transfer a phosphate group from ATP to a hexose sugar forming a phosphorylated sugar product.

Complete Answer:
phosphorylated at the 6th- C position by hexokinase. The hexokinase enzyme transfers a phosphate group from ATP to glucose and ADP is released as a result of this reaction.

Let us analyse the options to find the correct answer
- Option A: Transferases is a class of enzymes which catalyse the transfer of a functional group like methyl, acyl, alkyl, phosphate etc, to a substrate leading to formation of a product with that functional group. Examples include hexokinases, aminotransferases, etc. Hence, this is the correct option.
- Option B: Lyases Are a group of enzymes responsible for bond cleavage of C-C , C-O and C-N bonds by elimination reactions which are not oxidation or hydrolysis. One example is decarboxylases. Hence, this is an incorrect option.
- Option C: Oxidoreductases catalyse the transfer of electrons from a reductant to an oxidant using NAD+ or NADH as cofactors. Hence, this is the incorrect option.
- Option D: Isomerases are enzymes which catalyse the structural rearrangement of a molecule i.e change of a molecule from one isomer to another. Examples include triose phosphate isomerase. Hence, this is the incorrect option .

Thus, the correct answer is Option A) Transferases.

Note: Hexokinase performs the first step of glycolysis by phosphorylation of glucose, thus activating the pathway. It performs the rate limiting step of the pathway, thus helping to regulate glucose levels in our body. It utilizes ATP in the reaction. Hexokinase IV is called glucokinase which is mainly present in the liver.