Fully substituted quinones including some naturally occurring oxyquinones acted as inhibitors o f yeast gluta­ thione reductase (EC 1.6.4.2). They were competitive, mixed or uncompetitive inhibitors for N A D PH , possess­ ing K j in the range o f 1 2 0 0 |iM and uncompetitive in­ hibitors for glutathione. Rhein (4,5-dioxy-9,10-anthraquinone-2-carbonic acid) and 9,10-phenanthrenequinone were th...

Formation of the 2,3-dicyanohydroquinone (3) can be rationalised in terms of preferential addition of cyanide at the most electron deficient unsubstituted carbon of the cyanoquinone (2 ) in the same way as alcohols and other nucleophiles add to the 3-position of the acylquinone ( 8 ) [4], However, such an argu­ ment could not be applied to the formation of the dihydroxylamine (6 ). Hence, eithe...

Phytochemical studies of leaves and roots of the plant EchiumpycnanthumPomel (family Boraginaceae) revels thepresence of Flavonoids, Tannins, Quinones, Alkaloids, Saponins, Stérols and absence of Anthocyanes and Coumarines.

Nanostructured materials with tunable structures and functionality are of interest in diverse areas. Herein, metal ions coordinated quinones through metal-acetylacetone coordination bonds to generate a class structurally tunable, universally adhesive, hydrophilic, pH-degradable materials. A library metal-quinone networks (MQNs) is produced from five model quinone ligands paired nine ions, leadi...

Quinones are widely distributed substances of often potential toxicological significance. On the other hand, cyclic AMP is known to promote a cell-survival response and to retard apoptosis [Berridge, Tan and Hilton (1993) Exp. Hematol. 21, 269-276]. Therefore the effects of quinones on adenylate cyclase were tested. Adenylate cyclase is rapidly inhibited by quinones, with IC50 values of 40-45 m...

The reduction of the following exogenous quinones by succinate and NADH was studied in mitochondria isolated from both wild type and ubiquinone (Q)-deficient strains of yeast: ubiquinone-0 (Q0), ubiquinone-1 (Q1), ubiquinone-2 (Q2), and its decyl analogue 2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone (DB), duroquinone (DQ), menadione (MQ), vitamin K1 (2-methyl-3-phytyl-1,4-naphthoquinone), th...