Which macromolecule is primarily responsible for enzymatic function in biological systems?

Proteins are the macromolecules primarily responsible for enzymatic function in biological systems due to their ability to catalyze biochemical reactions. Enzymes, which are specific types of proteins, function by lowering the activation energy required for reactions, thus facilitating metabolic processes critical for life. The structure of proteins, which is determined by their amino acid sequence and folding, allows them to form specific active sites. These active sites bind substrates, enabling the conversion of substrates into products through various mechanisms.

In contrast, carbohydrates serve primarily as energy sources and structural components. Nucleic acids, such as DNA and RNA, play crucial roles in storing and transmitting genetic information and synthesizing proteins but do not have enzymatic activity themselves. Lipids, while important for energy storage and forming cell membranes, do not function as enzymes. This specificity of function highlights the unique role proteins play in catalysis within living organisms.