In vitro selection techniques were applied to the development of a DNA enzyme that contains three catalytically essential imidazole groups and catalyzes the cleavage of RNA substrates. Nucleic acid libraries for selection were constructed by polymerase-catalyzed incorporation of C5-imidazole-functionalized deoxyuridine in place of thymidine. Chemical synthesis was used to define a minimized cat...

Modified versions - paralogs - of the catalytic domain of at least three different aminoacyl-tRNA synthetases have been found to serve catalytic or regulatory roles in other reactions. These findings suggest that the first modern tRNA-synthetases could have been derived from amino-acid biosynthetic enzymes.

Enzymes, as biological catalysts, form the basis of all forms of life. How these proteins have evolved their functions remains a fundamental question in biology. Over 100 years of detailed biochemistry studies, combined with the large volumes of sequence and protein structural data now available, means that we are able to perform large-scale analyses to address this question. Using a range of c...

The cytochrome P450 enzymes are major catalysts involved in the oxidations of xenobiotic chemicals in microorganisms as well as higher animals and plants. Because of their functional roles, they offer potential in biodegradation technology. A number of microbial P450s have already been characterized and offer advantages in terms of their high catalytic rates and facile expression in microorgani...

Small molecule asymmetric catalysts are often described as being "good" or "bad" but to date there has been no way of comparing catalyst efficiency quantitatively. We define a simple formula, Asymmetric Catalyst Efficiency (ACE), that allows for such a comparison. We propose that a catalyst is more efficient if fewer atoms are utilised to give a product in a required enantiomeric excess. We ill...

Understanding which are the catalytic residues in an enzyme and what function they perform is crucial to many biology studies, particularly those leading to new therapeutics and enzyme design. The original version of the Catalytic Site Atlas (CSA) (http://www.ebi.ac.uk/thornton-srv/databases/CSA) published in 2004, which catalogs the residues involved in enzyme catalysis in experimentally deter...

We have coupled gold nanoparticles with horseradish peroxidase (HRP) to assemble catalytic nanoconjugates (HRP-AuNPs) for glucose detection. We found that a proper mixing ratio of HRP/AuNPs can significantly improve catalytic activity for the cascade reaction, an effect arising from increased spatial coupling between enzymes. Such gold nanoparticle-based nanoconjugates are shown to be promising...

Amino acid modifications of the Thermobifida fusca Cel9A-68 catalytic domain or carbohydrate binding module 3c (CBM3c) were combined to create enzymes with changed amino acids in both domains. Bacterial crystalline cellulose (BC) and swollen cellulose (SWC) assays of the expressed and purified enzymes showed that three combinations resulted in 150% and 200% increased activity, respectively, and...

Catalytic promiscuity and evolution: Many enzymes exhibit catalytic promiscuity--the ability to catalyze reactions other than their biologically relevant one. These reactions can serve as starting points for both natural and laboratory evolution of new enzymatic functions. Recent advances in the study of enzyme promiscuity in the tautomerase superfamily are discussed.

Well supported: stable hemin-graphene conjugates formed by immobilization of monomeric hemin on graphene, showed excellent catalytic activity, more than 10 times better than that of the recently developed hemin-hydrogel system and 100 times better than that of unsupported hemin. The catalysts also showed excellent binding affinities and catalytic efficiencies approaching that of natural enzymes.