(redirected from Ribozymes)
Also found in: Dictionary, Medical.


A ribonucleic acid (RNA) molecule that, like a protein, can catalyze specific biochemical reactions. Examples include self-splicing rRNA and RNase P, both involved in catalyzing RNA processing reactions (that is, the biochemical reactions that convert a newly synthesized RNA molecule to its mature form). Different ribozyme structures catalyze quite distinct RNA processing reactions, just as protein enzyme families that are composed of different structures catalyze different types of biochemical reactions.

Ribozymes share many similarities with protein enzymes, as assessed by two parameters that are used to describe a biological catalyst. The Michaelis-Menten constant Km relates to the affinity that the catalyst has for its substrate, and ribozymes possess Km values which are comparable to Km values of protein enzymes. The catalytic rate constant describes how efficiently a catalyst converts substrate into product. The values of this constant for ribozymes are markedly lower than those values observed for protein enzymes. Nevertheless, ribozymes accelerate the rate of chemical reaction with specific substrates by 1011 compared with the rate observed for the corresponding uncatalyzed, spontaneous reaction. Therefore, ribozymes and protein enzymes are capable of lowering to similar extents the activation energy for chemical reaction. See Enzyme, Protein, Ribonucleic acid (RNA)

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.


A ribonucleic acid molecule that can catalyze, or lower the activation energy for, specific biochemical reactions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Mentioned in ?
References in periodicals archive ?
Ribozyme rescue of photoreceptor cells in P23H transgenic rats: long-term survival and late-stage therapy.
The new enzyme is called a ribozyme because it is made from ribonucleic acid (RNA).
OK, but we also know that translation requires not only the ribozyme, but also the set of encoded protein enzymes that each properly load the appropriate transfer RNA with the "right" amino acid to that tRNA such that via its anticodon site it then binds to the "right" nucleotide triplet codon for the "right" amino acid for that position in the forming protein.
According to the RNA-first model, an RNA ribozyme arose in a prebiotic soup.
Molecular therapy (therapeutic genes, antisense, siRNAs, aptamers, and DNAzymes, ribozymes, peptides, proteins)
Sano et al., "Recognition of engineered tRNAs with an extended 3/ end by exportin-t (Xpo-t) and transport of tRNA-attached ribozymes to the cytoplasm in somatic cells," Biomacromolecules, vol.
Peng, "Polycationic dendrimers interact with RNA molecules: polyamine dendrimers inhibit the catalytic activity of Candida ribozymes," Chemical Communications, no.
Such applications include the generation of large quantities of RNA transcripts for translation, synthesis of tRNA, rRNA, RNA virus genomes, ribozymes, microarray targets [7], production of substrates for RNA splicing [8], RNA secondary structure, antisense RNA, and RNA-protein interaction studies.
Transfecting the cells with MVP-specific ribozymes inhibited these activities.
Other portions of the HCV genome that make potential antiviral targets include the internal ribosomal entry site (IRES) located in the 5\' noncoding region of the genome which is the most attractive target for ribozymes and antisense oligonucleotides.
(42) Technologies first developed in the 1980s and 1990s have been used to lab-evolve a wide variety of molecules, dubbed ribozymes in deference to the previously known class of protein catalysts known as enzymes.
Researchers know that ribozymes, enzymes that are able to target and cut specific RNA molecules, can be used to inactivate a pathogen's genes.