What is what macromolecule is an enzyme?

Enzymes are proteins. While some RNA molecules can have catalytic activity (ribozymes), the vast majority of enzymes are proteins. Their protein structure is crucial to their function. The specific three-dimensional folding of the polypeptide chain creates an active site, a region with a unique shape and chemical properties that allows the enzyme to bind to its substrate(s) and catalyze a specific reaction.