What is "synthase"

n. (context enzyme English) Any enzyme that catalyzes the synthesis of a biological compound but, unlike synthetases, does not make use of ATP as a source of energy

In biochemistry, a synthase is an enzyme that catalyses a synthesis process. Following the EC number classification, they belong to the group of ligases , with lyases catalysing the reverse reaction.

Note that, originally, biochemical nomenclature distinguished synthetases and synthases. Under the original definition, synthases do not use energy from nucleoside triphosphates (such as ATP, GTP, CTP, TTP, and UTP), whereas synthetases do use nucleoside triphosphates. However, the Joint Commission on Biochemical Nomenclature (JCBN) dictates that 'synthase' can be used with any enzyme that catalyzes synthesis (whether or not it uses nucleoside triphosphates), whereas 'synthetase' is to be used synonymously with 'ligase'.