What are enzymes classified as?

Enzymes are classified as biological catalysts because they accelerate chemical reactions within biological systems without being consumed in the reaction process. They play a crucial role in metabolism by lowering the activation energy required for reactions to occur, thus increasing the reaction rate significantly. This catalytic function is vital for numerous biochemical pathways, allowing organisms to maintain life by facilitating reactions such as digestion, energy production, and DNA replication.

Structurally, enzymes are typically proteins, which can lead to some confusion; however, their primary defining feature is their ability to catalyze reactions rather than their structural role. Energy carriers and storage proteins, while important in biological systems, serve different functions — energy carriers, like ATP, transport energy, and storage proteins, like casein or ovalbumin, serve to store amino acids or nutrients for later use. Thus, identifying enzymes primarily as biological catalysts highlights their essential function in the biochemistry of living organisms.