What type of protein acts as a biological catalyst?

Enzymes are a specific type of protein that function as biological catalysts. This means they accelerate biochemical reactions without being consumed in the process, allowing cellular processes to occur at rates that are compatible with life. Enzymes work by lowering the activation energy required for reactions to proceed, which makes it easier for the reactants to convert into products.

In contrast, hormones are signaling molecules that regulate physiological processes in the body, but they do not catalyze reactions. Structural proteins, such as collagen or keratin, provide support and shape to cells and tissues, while transport proteins facilitate the movement of substances across cell membranes or within the organism. Although these other types of proteins play crucial roles in biological systems, they do not have the catalytic properties that are characteristic of enzymes.