Which of the following are proteins produced by living organisms and which function as catalysts?

Enzymes are indeed proteins produced by living organisms that serve a crucial role as catalysts in biochemical reactions. They accelerate the rate of reactions by lowering the activation energy required for those reactions to occur. This catalytic function is essential for various metabolic processes, enabling organisms to efficiently convert substrates into products and facilitate biochemical pathways.

While hormones and antibodies are important biological entities, they do not primarily function as catalysts. Hormones act as chemical messengers that regulate physiological processes, and antibodies play a critical role in the immune response, targeting pathogens. Carbohydrates, on the other hand, are primarily energy sources and structural components, rather than catalysts. Thus, enzymes stand out specifically for their catalytic functions in biological systems.