What is the non-protein part of an enzyme called?

An enzyme is a .......

Which of the following statements is incorrect for enzymes?

Observe the following reactions:
$I$) $\text{Sucrose} (aq) + H_2O \xrightarrow{x} \text{glucose} + \text{fructose}$
$II$) $\text{Glucose} (aq) \xrightarrow{y} \text{ethanol} + CO_2$
What are $x$ and $y$ respectively?

Which enzyme converts starch into maltose?

Explain the catalytic action of enzymes.