What is an apoenzyme?

Which of the following statements is true regarding enzyme inhibition?

The enzyme $Lactate \text{ } Dehydrogenase$ belongs to which class of enzymes?

Name the class of enzyme that usually catalyzes the following reaction:
$S-G + S^* \rightarrow S + S^*-G$
Where,
$G \rightarrow$ a group other than hydrogen
$S \rightarrow$ a substrate
$S^* \rightarrow$ another substrate

What are enzymes composed of?

Which of the following enzymes is $NOT$ regulated by calcium?