A chloroplast type of fructose-1,6-bisphosphatase, a central regulatory enzyme of photosynthetic carbon metabolism, has been partially purified from Chlamydomonas reinhardtii. Unlike its counterpart from spinach chloroplasts, the algal FBPase showed a strict requirement for a dithiol reductant irrespective of Mg2+ concentration. The enzymes from the two sources resembled each other immunologic...

L-Tryptophan-2,3-dioxygenases (EC 1.13.1.12), purified to homogeneity from Pseudomonas acidovorans and from rat liver, have been shown to contain as bound cofactors, 2 g atoms copper and 2 moles of heme per mole of tetrameric enzyme. Kinetic and spectral studies, utilizing the metal complexing agents diethyldithiocarbamate (Cu2+ specific), bathocuproinesulfonate (Cu+ specific), and bathophenant...

Although the pseudohalide thiocyanate (SCN(-)) is the preferred substrate for eosinophil peroxidase (EPO) in fluids of physiologic halide composition, the product(s) of this reaction have not been directly identified, and mechanisms underlying their cytotoxic potential are poorly characterized. We used nuclear magnetic resonance spectroscopy (NMR), electrospray ionization mass spectrometry, and...

Little is known about the mechanisms by which Treponema pallidum (Tp), the causative agent of syphilis, copes with oxidative stress as it establishes persistent infection within its obligate human host. The Tp genomic sequence indicates that the bacterium's antioxidant defenses do not include glutathione and are limited to just a few proteins, with only one, TP0509, offering direct defense agai...

Uncharged reductants, such as NNN'N'-tetramethyl-p-phenylenediamine and diaminodurene, reduce cytochrome c at both high and low ionic strength, unlike ascorbate, which is effective only at low ionic strength. The 'tightly bound' cytochrome c-cytochrome c oxidase complex, with 1 equiv. of cytochrome c per cytochrome aa3, can be prepared by simple mixing of the two component species. Its properti...

Addition of reducing agents to competitive assays for antibody to hepatitis B core antigen (anti-HBc) eliminates apparent false reactivity of specimens obtained from individuals with no prior history of hepatitis B virus (HBV) infection and without other serological markers of HBV infection. We have purified and characterized a reduction-sensitive factor (RSF) isolated from the plasma of severa...

Under physiological conditions, the Escherichia coli cytoplasm is maintained in a reduced state that strongly disfavors the formation of stable disulfide bonds in proteins. However, mutants in which the reduction of both thioredoxins and glutathione is impaired (trxB gor mutants) accumulate oxidized, enzymatically active alkaline phosphatase in the cytoplasm. These mutants grow very poorly in t...