A thiosulfate reductase from Desulfotomaculum nigrificans has been partially purified by ammonium sulfate fractionation, diethylaminoethylcellulose chromatography, and sucrose density gradient centrifugation. With inner-and outer-labeled (35)S-thiosulfate, the enzyme reduced only the outer sulfur atom to hydrogen sulfide. The enzyme was inhibited by sulfite and also by several sulfhydryl inhibi...

We have shown in a previous communication (1) that the enzyme triosephosphate dehydrogenase is rapidly inactivated in the presence of reduced diphosphopyridine nucleotide at physiological concentrations, temperature, and pH. Good stoichiometry was shown for the amount of enzyme inactivation, DPNH-X1 formation, and disappearance of sulfhydryl groups. It was then of particular interest to determi...

An overview of the literature concerning the effects of thimerosal is presented. Because of its antibacterial effect, thimerosal is used for a variety of practical purposes such as antiseptic and preservative. In biomedical studies, thimerosal is used as a sulfhydryl reagent, and as a calcium-mobilizing agent. The ability of thimerosal to act as a sulfhydryl group is related to the presence of ...

Enzyme I is the first protein of the phospho transfer sequence in the bacterial phosphoenolpyruvate:glycose phosphotransferase system. This protein exhibits a temperature-dependent monomer/dimer equilibrium. The nucleotide sequence of Escherichia coli ptd indicates four -SH residues per subunit (Saffen, D. W., Presper, K. A., Doering, T. L., and Roseman, S. (1987) J. Sol. Chem. 262, 16241-16253...

17 β -Hydroxysteroid dehydrogenase type 1 (17 β -HSD1) catalyzes the conversion of estrone to the potent estrogen estradiol. 17 β -HSD1 is highly expressed in breast and ovary tissues and represents a prognostic marker for the tumor progression and survival of patients with breast cancer and other estrogen-dependent tumors. Therefore, the enzyme is considered a promising drug target against est...

Experiments with honeybee (Apis mellifera)and rabbit muscle GPDH were conducted to obtain information at the chemical level regarding anomolous saturation kinetics of the honeybee enzyme. Results demonstrate that the enzyme's sulfhydryl groups are implicated in the process. Measured by DTNB titration, native honeybee GPDH has one less active SH than the native rabbit muscle enzyme and displays ...

Experiments with honeybee (Apis mellifera)and rabbit muscle GPDH were conducted to obtain information at the chemical level regarding anomolous saturation kinetics of the honeybee enzyme. Results demonstrate that the enzyme's sulfhydryl groups are implicated in the process. Measured by DTNB titration, native honeybee GPDH has one less active SH than the native rabbit muscle enzyme and displays ...

Hydrodynamic, chemical, and optical properties of arginine deiminase (EC 3.5.3.6) from Mycoplasma arthritidis are reported for the enzyme isolated from log phase cells. The s& +, and D’& values of the enzyme are 5.48 S and 5.87 x 10V7 cm’/s, respectively; the molecular weight is 87,300. Determination of the amino acid composition shows that about 45% of the residues are nonpolar. Another unique...

The dissociations of porcine heart mitochondrial, bovine heart mitochondrial, and porcine heart cytoplasmic malate dehydrogenase dimers (I,-malate: NAI)’ oxidoreductase, EC 1.1.1.37) have been examined by Sephadex G-100 gel filtration chromatography and sedimentation velocity ultracentrifugation. The porcine mitochondrial enzyme was found to chromatoyraph as subunits when applied to a gel filtr...