DNAzymes, deoxyribozymes, or simply DNA enzymes, are single-stranded DNA molecules that, like proteins and ribozymes, possess the ability to adopt complex 3D folds in order to perform catalysis. Although DNAzymes have not been found in nature, they can be isolated in the laboratory through in vitro selection, which imitates natural selection but in a very accelerated time scale. In this process, a pool containing millions of DNA molecules is subjected to repeated rounds of selective amplification, and only the DNA molecules capable of performing the desired catalytic function will be replicated.