By Dr Ananya Mandal, MD
A ribozyme is a ribonucleic acid enzyme or RNA enzyme that catalyzes a chemical reaction. The ribozyme catalyses specific reactions in a similar way to that of protein enzymes.
Also called catalytic RNA, ribozymes are found in the ribosome where they join amino acids together to form protein chains. Ribozymes also play a role in other vital reactions such as RNA splicing, transfer RNA biosynthesis, and viral replication.
The first ribozyme was discovered in the early 1980s and led to researchers demonstrating that RNA functions both as a genetic material and as a biological catalyst. This contributed to the worldwide hypothesis that RNA may have played a crucial role in the evolution of self-replicating systems.
Many naturally occurring ribozymes either aid the hydrolysis of their own phosphodiester bonds or cause the hydrolysis of bonds in other RNAs. They also catalyze the aminotransferase activity of the ribosome.
Researchers have developed synthetic ribozymes in the laboratory that are able to catalyze their own synthesis under specific conditions. One example is the RNA polymerase ribozyme. Using mutagenesis and selection, scientists have managed to develop and improve variants of the Round-18 polymerase ribozyme from 2001. The best variant so far is called B6.61, which can add up to 20 nucleotides to a primer template over a period of 24 hours. After 24 hours, the hydrolysis of its phosphodiester bonds causes the ribozyme to decompose.
Ribozymes may also play an important role in therapeutic areas, acting as molecules that can tailor specific RNA sequences, acting as biosensors and providing a useful tool in applications such as gene research and functional genomics.
Reviewed by Sally Robertson, BSc
Last Updated: Sep 16, 2014