Abstract
The discovery of natural RNA enzymes (ribozymes) prompted the pursuit of artificial DNA enzymes (deoxyribozymes) by in vitro selection methods. A key motivation is the conceptual and practical advantages of DNA relative to proteins and RNA. Early studies focused on RNA-cleaving deoxyribozymes, and more recent experiments have expanded the breadth of catalytic DNA to many other reactions. Including modified nucleotides has the potential to widen the scope of DNA enzymes even further. Practical applications of deoxyribozymes include their use as sensors for metal ions and small molecules. Structural studies of deoxyribozymes are only now beginning; mechanistic experiments will surely follow. Following the first report 21 years ago, the field of deoxyribozymes has promise for both fundamental and applied advances in chemistry, biology, and other disciplines.