decarboxylase Syllabification: (de·car·box·yl·ase)Pronunciation: /ˌdēkärˈbäksəˌlās, -ˌlāz/Definition of decarboxylase noun Biochemistry an enzyme that catalyzes the decarboxylation of a particular organic molecule. decarboxylase in other Oxford dictionaries Definition of decarboxylase in the British & World English dictionary