Deoxyribozymes - DNA Molecules with Catalytic Properties

While there is still no demonstration that DNA carries out catalytic functions in present-day biology, numerous DNAzymes have been developed by in vitro selection. While the spectrum is not as wide as for ribozymes, it clearly goes far beyond what was imagined 

DNAzymes can also cleave DNA. This is, however, achieved by an oxidative mechanism involving freely diffusible hydroxyl radicals. The site and sequence specificity of cleavage is low, limiting the synthetic utility of these enzymes. 

Many DNAzymes catalyse RNA ligation reactions to yield linear, branched, and lariat-type reaction products. The ligation of DNA strands as well as the phosphorylation of DNA or RNA oligonucleotides was described. Some notable extensions beyond phosphodiester chemistry include a photoreversion reaction, a deglycosylation, porphyrin metalation, nucleopeptide bond formation, and finally a Diels-Alder reaction. This latter reaction is essentially the same studied by the Jaschke lab with RNA as a catalyst (as discussed below in more detail), and the information published to-date indicates that the catalytic proficiency of DNA and RNA enzymes for Diels-Alder reactions is very similar. 

Like in the case of RNA, DNAzymes were oeated with a variety of side chains , ranging from imidazol groups to primary amines and imidines.  

---