Ribozyme. Computer model of a ribozyme molecule. Ribozymes are RNA (ribonucleic acid) molecules that catalyse certain biochemical reactions. Until their discovery in the 1980s it was thought only proteins had this ability. Most ribozymes catalyse their own cleavage, or that of other RNAs, but some also have roles within ribosomes, the location of protein synthesis. The discovery of ribozymes has strengthened the argument that RNA was the first life-form on Earth and carried out the functions performed by both DNA (deoxyribonucleic acid) and proteins today.