We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozy...

I102 does C5, and with slightly greater efficiency. Kinetic properties for these reactions have not been determined yet, but the rate enhancements above background are not as large as for the original substrate 7. The presence of the amino group opens additional mechanisms for the reaction of 8 and 9 in which the amino group acts as a nucleophile or as a general base. The latter mechanism would...

Hydrolysis of cyanuric acid, melamine, melem, atrazine and melamine-formaldehyde resin was found to be catalyzed by an A1203 catalyst. The reactions occur irreversibly with cleavage of the s-triazine ring between 240 and 450°C. The s-triazine-ring is hydrolyzed to ammonia and carbon dioxide, and the substituted groups to the corresponding molecules by addition of hydrogen.

cGMP-phosphodiesterases of the PDE6 family are expressed in retinal photoreceptor cells, where they mediate the phototransduction cascade. A system for expression of PDE6 in vitro is lacking, thus straining progress in understanding the structure-function relationships of the photoreceptor enzyme. Here, we report generation and characterization of bacterially expressed chimeric PDE5/6 catalytic...

Sorption and catalytic hydrolysis of the herbicide diethatyl-ethyl [N-chloroacetyl-N-(2,6-diethylphenyl)glycine ethyl ester] on homoionic Na(+)-, K(+)-, Ca(2+)-, and Mg(2+)-montmorillonite clays were studied in aqueous media. The Freundlich sorption coefficient, K(f), measured from isotherms on clay followed the order of Na(+) approximately K(+) > Mg(2+) approximately Ca (2+). Analysis of FT-IR...

The activation and catalytic mechanism of corn mitochondrial F(1) were examined for the two distinct forms of the enzyme which appear upon storage in ammonium sulfate or glycerol. Apparently irreversible differences in the stability of the two active forms were found. Nucleosidetriphosphate induced activation of the enzyme was found to produce lasting effects on subsequent catalysis. These effe...

The oxygen exchange parameters for the hydrolysis of ATP by the F1-ATPase have been determined over a 140,000-fold range of ATP concentrations and a 5,000-fold range of reaction velocity. The average number of water oxygens incorporated into each Pi product ranges from a limit of about 1.02 at saturating ATP concentrations to a limit of about 3.97 at very low ATP concentrations. The latter valu...

Bacillus circulans chitinase A1 (ChiA1) has a deep substrate-binding cleft on top of its (beta/alpha)8-barrel catalytic domain and an interaction between the aromatic residues in this cleft and bound oligosaccharide has been suggested. To study the roles of these aromatic residues, especially in crystalline-chitin hydrolysis, site-directed mutagenesis of these residues was carried out. Y56A and...