By sulfur substitution of the N-5 atom in flavins and flavocoenzymes a flavin analog is obtained, Sthiaflavin, which is found to be isoelectronic and isosteric with natural flavin in the fully reduced and half-reduced states, but not in the oxidized state. Among the three ‘redox shuttles’ characterizing the flavin system, viz. upper le-, lower leand 2eshuttle, only the second one is retained in...

The thyroid plasma membrane contains a Ca2(+)-regulated NADPH-dependent H2O2 generating system which provides H2O2 for the thyroid peroxidase-catalyzed biosynthesis of thyroid hormones. The plasma membrane fraction contains a Ca2(+)-independent cytochrome c reductase activity which is not inhibited by superoxide dismutase. But it is not known whether H2O2 is produced directly from molecular oxy...

The interaction between POCl(3) or POBr(3) and pyridine or DMAP has been reinvestigated to clarify the discrepancies between previously published results concerning the Lewis acidity of phosphoryl halides and their behavior toward pyridine bases. The obtained results show that POCl(3) virtually does not react with pyridine, while it does with 4-(dimethylamino)pyridine (DMAP), even in SO(2) solu...

The Mn(III) meso -tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnIIITE-2PyP5+, is a potent SOD mimic in vitro, and was beneficial in rodent models of oxidative stress pathologies. Its high activity has been ascribed to both the favorable redox potential of its metal center and to the electrostatic facilitation assured by the four positive charges encircling the metal center. Its comparison with t...

Abstract Molecular β‐diketiminato (BDI) calcium hydride and n ‐hexyl derivatives are shown to display contrasting reactivities toward bis(pinacolato)diboron (B 2 pin ). Whereas the dimeric constitution of is retained during formation an unusual diborane(6) dianion, initially organocalcium reagent converted a diboranate monomer, [(BDI)Ca{pinB‐Bpin( ‐hex)}]. Attempts effect heterolysis B−B bond t...