The enzymes which catalyse the non-hydrolytic removal of a chemical group from a substrate are:

Explanation

Lyases are a class of enzymes that catalyze the non-hydrolytic removal or addition of groups to substrates, often resulting in the formation or breaking of double bonds. They are distinct from other enzyme classes because they do not require water to break bonds, unlike hydrolases. Instead, they facilitate the conversion of molecules by removing functional groups, such as carbon dioxide or ammonia, without the need for hydrolysis. e.g: Histidine decarboxylase breaks the covalent bond between carbon atoms in histidine forming carbon dioxide and histamine.Ligases, on the other hand, are involved in forming new bonds between molecules, typically requiring energy input from ATP. Isomerases catalyze the rearrangement of atoms within a molecule, altering its geometric or structural form. Transferases are responsible for transferring functional groups between molecules, such as methyl or phosphate groups.Therefore, the correct answer is lyases, as they specifically match the description of enzymes that catalyze the non-hydrolytic removal of a chemical group from a substrate.