enzymes, proteins present in all biological systems that act as catalysts by inducing or accelerating specific biochemical reactions. Enzymes, named using the suffix -‘ase’, are characterized by both the specificity of the chemical group or substrate they act on and the reaction which they catalyse. Endogenous enzymes are those that the organism itself produces whereas exogenous enzymes are those that are prepared commercially.
Endogenous enzyme activities of the vine are central to the biological processes by which grape berries develop and ripen. Wine is the enzymatic transformation or fermentation of grape juice by thousands of endogenous enzymes originating from the grape juice, yeast cells and other microbes.