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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)


A ribonucleic acid molecule that can catalyze, or lower the activation energy for, specific biochemical reactions.
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However, we believe that the second mechanism may be advantageous to synthesize large RNA by primitive catalytic RNA, and ribozymes with RNA ligation activity might have been an essential catalytic activity in t he RNA world.
Noting the diversity of potential chemical paths available to HMU, they argue that ancient catalytic RNA would have had much greater "efficiency and versatility" than researchers have realized.
The 'RNA world' hypothesis claims that ancient life forms employed a variety of different catalytic RNA in their biosynthetic machinery.
The uniform product of all such reactions is released pyrophosphate, and the RNA product has the attacking phosphate linked to the 5[prime] [Alpha]-phosphate of the catalytic RNA.
In another anti-gene approach, scientists make their own ribozymes--bits of catalytic RNA that chew up other strings of this nucleic acid (SN: 12/22&29/90, p.
Ribozymes, also known as catalytic RNA and "molecular scissors," are molecules that can break down nucleic acid inside a cell, thus they can be used to cut out "bad" genetic information and splice in "good" material.
Wally Bugg won Outstanding Undergraduate Presentation award for his work on the "Isolation of a Catalytic RNA Capable of Coenzyme Synthesis" conducted under the direction of Faqing Huang (University of Southern Mississippi.
founded in 1989, is a biotechnology company developing External Guide Sequences (EGSs), a patented, broad enabling technology based on catalytic RNA known as ribozymes.
In order to demonstrate the ability of RNA to catalyze the synthesis of coenzymes from their precursors, catalytic RNA is being isolated by powerful in vitro selection/amplification techniques from a pool of random RNA sequences.
He reported using chemical "selection pressures" to coax an actual ribozyme -- a segment of catalytic RNA that cuts itself out of a longer RNA molecule -- to evolve into a form that cuts DNA molecules instead.

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