An
enzyme or enzyme complex consisting of, or derived from, an organism or cell culture (in
cell-free or whole-cell forms) that catalyses metabolic reactions in living organisms
and/or
substrate conversions in various chemical reactions.
Source:
PAC, 1992, 64, 143
(Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992))
on page 147