Name the class of enzyme that usually catalyze the following reaction :

S – G + S^# → S + S^# – G

Where, G → a group other than hydrogen

S → a substrate

S^# → another substrate

**Identify the type of chemical change**

The given reaction is

$S\; –\; G\; +\; S\#\to \; S\; +\; S\#–\; G$

Here a specific group **G** (which is not hydrogen) is removed from substrate **S** and attached to a different substrate **S#**. The overall transformation merely moves the group from one molecule to another without adding or removing atoms from the system.

**Classify the enzyme based on the reaction pattern**

Enzyme classes are defined by the kind of chemical transformation they catalyze:

• Lyase: breaks bonds without hydrolysis or oxidation, often forming a new double bond.
• Transferase: transfers a functional group (e.g., phosphate, methyl, glycosyl) from one molecule to another.
• Ligase: joins two molecules together with the concomitant hydrolysis of ATP (or another nucleoside triphosphate).
• Hydrolase: catalyzes bond cleavage by adding water.

The reaction does **not** involve cleavage by water, formation of a new double bond, or ATP‑driven bond formation. It exclusively transfers the group **G** from **S** to **S#**.

**Conclusion**

Because the defining feature of the reaction is the transfer of a non‑hydrogen group from one substrate to another, the enzyme that catalyzes it belongs to the **transferase** class.