Substrate Specificity of Mammalian D-Glucuronolactone Dehydrogenase

Metabolism of D-glucuronolactone in mammalian systems. Inhibitory properties of the products of D-glucuronolactone-dehydrogenase action.

1. d-Glucuronolactone was converted into d-glucaro-(1-->4)-lactone, a beta-glucuronidase inhibitor, probably via the intermediate d-glucaro-(1-->4)-(6-->3)-dilactone, by a dehydrogenase in human-liver extracts. 2. Similar experiments with mouse-liver extracts appeared to yield only d-glucaric acid or a non-inhibitory lactone. 3. A strong beta-glucuronidase inhibitor was present in mouse liver a...

Metabolism of D-glucuronolactone in Mammalian Systems. 3. Further Studies of D-glucuronolactone Dehydrogenase of Rat Liver.

Substrate specificity of mammalian pyridine nucleotide transglycosidases.

Spectrophotometrical analysis of pyridine nucleotide transglycosidase in mammalian tissues indicated that the enzyme activity was observed to be distributed ubiquitously among the mammalian tissues analyzed, although the velocity ratio of transglycosidation/hydrolysis (vT/vH) and the partitioning of nicotinic acid against water differed with the pyridine nucleotide substrate and the mammalian s...

Substrate Specificity of d Ribozyme Cleavage

The specificity of d ribozyme cleavage was investigated using a trans-acting antigenomic d ribozyme. Under single turnover conditions, the wild type ribozyme cleaved the 11-mer ribonucleotide substrate with a rate constant of 0.34 min, an apparent Km of 17.9 nM and an apparent second-order rate constant of 1.89 3 10 min M. The substrate specificity of the d ribozyme was thoroughly investigated ...

Substrate specificity of the pyruvate dehydrogenase complex from Escherichia coli.

The investigation of the substrate specificity of the pyruvate dehydrogenase complex from Escherichia coli allows a description of the binding region of pyruvate. Substrate analogs with electronegative substitutions in the methyl group show a strong competitive inhibition of the overall reaction of the pyruvate dehydrogenase complex. The most efficient inhibitor is fluoropyruvate which has a mo...