1. Something that causes an important event to happen.
2. (Chemistry) A substance that initiates or accelerates a chemical reaction without itself being affected; SYN. accelerator.
A substance that changes the speed or yield of a chemical reaction without being consumed or chemically changed by the chemical reaction
Substance that alters the speed of, or makes possible, a chemical or biochemical reaction but remains unchanged at the end of the reaction. Enzymes are natural biochemical catalysts. In practice most catalysts are used to speed up reactions. + prikaži više