What is a primary role of polypeptides in the body?

Polypeptides play a critical role in the body as catalysts for biochemical reactions, primarily through their function as enzymes. Enzymes are specialized proteins that accelerate chemical reactions necessary for various biological processes, including metabolism, DNA replication, and cellular signaling. This catalytic activity allows for reactions to occur at rates conducive to life, as many biochemical reactions would be too slow without the presence of these enzymes.

In addition to their enzymatic functions, polypeptides are involved in numerous other essential biological roles, such as signaling molecules, structural components, and as antibodies, contributing to the overall complexity and functionality of living organisms. However, their primary distinguishing feature in this context is their role in catalyzing reactions, which is fundamental to maintaining life processes at the cellular and organismal levels.