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The objective of this work was to contribute to the understanding of mechanisms for IMPDH inhibition. We over-expressed hamster type II IMPDH in Escherichia coli, purified the protein to apparent homogeneity, and used capillary electrophoresis to quantify enzyme turnover events accompanying inhibition by mycophenolic acid (MPA). We dissected two convergent(More)
The chelating agents 1,10-phenanthroline and 2,2'-dipyridyl gave partial inhibition of the bovine lens aldehyde dehydrogenase, which was fully reversible and competitive towards acetaldehyde. The non-chelating compounds, 1,7-phenanthroline, 4,7-phenanthroline and 4,4'-dipyridyl gave total competitive inhibition, and significant activation at saturating(More)
When serious multicollinearity is detected in the data, some corrective actions should be taken in order to reduce its impact. The remedies for the problem of multicollinearity depend on the objective of the regression analysis. Multicollinearity causes no serious problem if the objective is to predict. However, multicollinearity is a problem when our(More)
A comparison of the inactivation of bovine carbonic anhydrase B (carbonate hydro-lyase, EC 4.2.1.1) by OH, (SCN)(2) and Br(2) shows that the enzyme contains one or more essential tryptophan residues. Direct oxidation of histidine and tyrosine residues by the radicals is less important in causing inactivation of the enzyme. The effectiveness of all these(More)
Human lens was found to contain aldehyde dehydrogenase at a level of activity similar to that of bovine lens, namely 1.76 +/- 0.51 IU/g. The enzyme, which appears to be a tetramer of 229 kD, was less susceptible to inhibition by cataractogenic agents than the bovine enzyme. The lipid peroxidation product malondialdehyde was a good substrate of the human(More)
Reactions of the inorganic radical anions, Br(2) and (SCN)2, with bovine carbonic anhydrase (carbonate hydrolyase, EC 4.2.1.1) have been studied by pulse radiolysis. Reaction is almost completely inhibited by the binding of Br-, SCN- and ClO4- to an electrophilic site at the active centre of the enzyme. Dissociation constants for anion binding calculated(More)
Using Chinese hamster V79 cells in vitro a study has been made of the radiosensitizing properties of 4- or 5-nitroimidazoles substituted in the 2, 5 or 4 position with various halo, sulphur ether, sulphonamide, sulphonate, ether or nitro groups. Values of E17 (the one-electron reduction potential measured versus the normal hydrogen electrode at pH7) vary in(More)
Various 5-substituted 4-nitroimidazoles have been shown to be much more efficient radiosensitizers and much more toxic than would have been predicted from their electron affinities, as measured by values of one-electron reduction potential, E17. Using Chinese hamster V79 cells in vitro, a comparison has been made with some isomeric 4-substituted(More)