Ribozymes, RNA molecules, present in the enzyme can function as enzymes. Altman and coworker in 1983 found that ribonuclease P (Figure 6.33), an enzyme-cleaved precursor of tRNA, was functional due to RNA component present in the enzyme and not protein part of the enzyme. This RNA ribozymes also obey Michaelis-Menten kinetics.

Figure 6.33 Ribozyme–Ribonuclease P