We have advanced a mechanism for nitrogenase catalysis that rests on the identification of a low-spin EPR signal (S = 1/2) trapped during turnover of a MoFe protein as the E4 state, which has accumulated four reducing equivalents as two [Fe-H-Fe] bridging hydrides. Because electrons are delivered to the MoFe protein one at a time, with the rate-limiting step being the off-rate of oxidized Fe pr...

Sonicated mitochondria catalyse the reduction of ferric salts, and the subsequent incorporation of Fe(2+) into haem, when provided with a reducing substrate such as succinate or NADH. The rate of haem synthesis was low under aerobic conditions and, after a short lag period, accelerated once anaerobic conditions were achieved; it was insensitive to antimycin A. The lag period was decreased by pr...

Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chromatographic methods including semi-preparative HPLC afforded three new (1-3) and six known (4-10) acylphloroglucinols alongside a known dialcohol triterpene (11). The structures of the isolated compounds were characterized accordingly as 1-benzoyl-3 (3-methylbut-2-enylacetate)-phloroglucinol (helin...

Thermoanaerobacter indiensis BSB-33 has been earlier shown to reduce Fe(III) and Cr(VI) anaerobically at 60°C optimally. Further, the Gram-positive thermophilic bacterium contains Cr(VI) reduction activity in both the membrane and cytoplasm. The soluble fraction prepared from T. indiensis cells grown at 60°C was found to contain the majority of Fe(III) reduction activity of the microorganism an...

butyl-hydroxytoluene (bht) is one of the major synthetic antioxidants with a wide range usage. replacement of artificial antioxidants with natural antioxidants is highly considered. in this research, the antioxidant activity of juniperus excelsa was investigated by using reducing power, dpph radical scavenging and inhibition of lipid peroxidation. also, the amounts of phenolic and flavonoid com...

Partially reduced graphene oxide functionalized with Fe nanoparticles alone or combined with Au and Pt nanoparticles is synthesized and characterized, and their effects on Polymer Electrolyte Membrane Fuel Cell (PEMFC) power output and carbon monoxide resistance are tested. Samples were prepared with various combinations of metal nanoparticles to create a cost-effective catalyst. Transmission a...

Seaweeds have been introduced as an important sources of food and pharmaceutical active agents since last century. In this study, the chemical composition and functional characteristics of (common names) Nizamuddinia zanardinii and Iyengaria stellata, were investigated. The total carbohydrate and ash contents were the two most abundant components in these seaweeds but their crude lipid and fibe...

Different root parts with or without increased iron-reducing activities have been studied in iron-deficient and iron-sufficient control sugar beet (Beta vulgaris L. Monohil hybrid). The distal root parts of iron-deficient plants, 0 to 5 mm from the root apex, were capable to reduce Fe(III)-chelates and contained concentrations of flavins near 700 microM, two characteristics absent in the 5 to 1...

Comparative antioxidant activities of the water and ethanol extracts obtained from dried citrus fruit (Citrus unshiu) peel were determined using chemical and biochemical in vitro assays. Chemical assays were used for evaluation of 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, hydrogen peroxide scavenging, and reducing power of both extracts and their total phenolic, flavonoid and ta...