- An RNA molecule that can catalyze its own chemical reactions.
* * *A nonprotein biocatalyst; several cleave precursors of tRNA to yield functional tRNAs; others act on rRNA; plays a key role in intron splicing events. SYN: organic catalyst (1), RNA enzyme. [ribonucleic acid + -zyme]
* * *ri·bo·zyme 'rī-bə-.zīm n a molecule of RNA that functions as an enzyme (as by catalyzing the cleavage of other RNA molecules)
* * *n.an RNA molecule that can act as an enzyme, catalysing changes to its own molecular structure (before the discovery of ribozymes it was assumed that all enzymes were proteins). Since replication of DNA and RNA cannot occur without enzymes, and since protein enzymes can only be produced by DNA coding, the question arose as to how nucleic acid molecules were able to replicate in the early stages of evolution. The discovery of ribozymes appears to resolve the enigma. Research is currently being undertaken to exploit the ability of genetically engineered ribozymes to destroy the RNA of HIV (the AIDS virus).
* * *ri·bo·zyme (riґbo-zīm″) [ribonucleic acid + -zyme] an RNA molecule with catalytic activity; different classes exist, and the reactions they catalyze may be intramolecular, e.g., self-splicing, or intermolecular, e.g., maturation of tRNA molecules. Secondary and tertiary structure is important to activity.
Medical dictionary. 2011.