What type of biological molecule are enzymes classified as?

Enzymes are classified as proteins due to their structure and function. Proteins are composed of long chains of amino acids, which fold into specific shapes that are crucial for their activity. Enzymes act as biological catalysts, facilitating chemical reactions by lowering the activation energy required for these reactions to occur. The specificity of enzymes, meaning that each enzyme typically catalyzes only one type of reaction or a group of closely related reactions, is governed by their unique three-dimensional structure, which is derived from their amino acid sequence.

In enzymatic reactions, the substrate binds to the active site of the enzyme, resulting in a temporary enzyme-substrate complex that enables the conversion of substrate into products. This process underlines the importance of proteins in biological systems, where enzymes play critical roles in metabolism, signal transduction, and numerous other cellular processes.

While lipids, carbohydrates, and nucleic acids are essential biomolecules with vital roles in energy storage, structural components, and genetic information, they do not possess the catalytic functions that enzymes provide. This distinctive feature identifies enzymes specifically as proteins, emphasizing their role in biological catalysis.