A novel flavoprotein monooxygenase, 4-hydroxybenzoate 1-hydroxylase (decarboxylating), from Candida parapsilosis CBS604 was purified to apparent homogeneity. The enzyme is induced when the yeast is grown on either 4-hydroxybenzoate, 2,4-dihydroxybenzoate, or 3,4-dihydroxybenzoate as the sole carbon source. The purified monooxygenase is a monomer of about 50 kDa containing flavin adenine dinucle...

A library of 206 extracts from selected South African plants was screened in vitro against a panel of protozoan parasites, Plasmodium falciparum, Trypanosoma brucei rhodesiense, and Leishmania donovani. A CH2Cl2/MeOH (1 : 1) extract of Abrus precatorius L. ssp. africanus strongly inhibited P. falciparum (98 %), T. b. rhodesiense (100 %), and L. donovani (76 %) when tested at a concentration of ...

The electrochemically induced mass spectrometric tagging of cysteines by substituted hydroquinones was studied for peptides in a classical electrospray solvent (i.e., MeOH/H2O/AcOH 50/49/1). The tagging efficiency was tested with different hydroquinone compounds on an undecapeptide containing one cysteine residue. 2-carboxymethylhydroquinone was the most reactive probe and revealed to be suitab...

NAD(P)H:quinone oxidoreductase 1 (NQO1), is a cytosolic flavoenzyme that catalyzes the two-electron reduction of quinones into hydroquinones. A polymorphism (NQO1*2) alters enzymatic activity of NQO1 resulting in diminished NQO1 activity. Malignancies with NQO1*2 may be resistant to radiation and chemotherapy with resulting poorer survival. NQO1 allele was evaluated in subjects enrolled in ECOG...

PURPOSE NAD(P)H quinone oxidoreductase (NQO(1)) catalyzes the two-electron reduction of quinones to hydroquinones. This reaction is believed to prevent the one-electron reduction of quinones that would result in redox cycling with generation of superoxide (O(2)(.-)). We have recently demonstrated that inhibition of NQO(1) with dicumarol increases intracellular O(2)(.-) production and inhibit...

Marine sponges of the Irciniidae family contain both bioactive furanosesterterpene tetronic acids (FTAs) and prenylated hydroquinones (PHQs). Both classes of compounds are known for their anti-inflammatory, antioxidant, and antimicrobial properties and known to display growth inhibitory effects against various human tumor cell lines. However, the different experimental conditions of the reporte...

NADPH:quinone oxidoreductase (NQO(1)), a homodimeric, ubiquitous, flavoprotein, catalyzes the two-electron reduction of quinones to hydroquinones. This reaction prevents the one-electron reduction of quinones by cytochrome P450 reductase and other flavoproteins that would result in oxidative cycling with generation of superoxide (O(2)(.-)). NQO(1) gene regulation may be up-regulated in some tum...

The recent trials of gentisic acid as a therapeutic agent (1, 2)’ stimulated our interest in the development of methods for the determination of gentisic acid in serum. Meyer and Ragan (1) referred to a method which is suitable for the analysis of gentisic acid in urine. No details were given. Although they were able to detect 5 y of hydroquinone per ml. in urine (l), they did not find detectab...