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تبدیل هیدرازونوآمیدن های حلقوی به مشتقات آمینوپیرازولو مربوطه سپس حلقه زایی بین گروههای آمینوپیرازول و nh آمیدین حلقوی منجر به ایجاد سیستم های حلقوی: 8و9- دی هیدرو- h7- پیرازولو ]1،5-c [ پیریمیدو ]1،2-[a ]1،3،5[ تری آزین-3- ایل سیانیدو .... (5-8) می شوند. پیرازولوپیریمیدو تری آزین از 2- هیدروزین پیریمیدنهایی تهیه شده اند که آنها نیز به سهولت از آمونولیز 2-متیل تیوپیریمیدین (1a,1b) سنتز شده اند ...
In recent studies we demonstrated that systemic levels of protein-bound nitrotyrosine (NO(2)Tyr) and myeloperoxidase (MPO), a protein that catalyzes generation of nitrating oxidants, serve as independent predictors of atherosclerotic risk, burden, and incident cardiac events. We now show both that apolipoprotein A-I (apoA-I), the primary protein constituent of HDL, is a selective target for MPO...
Several large-scale, multi-centered trials have demonstrated that 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors, or “statins” as they are often called, are effective in lowering total cholesterol and LDLcholesterol levels by up to 25% and 35%, respectively, and in raising HDL-cholesterol levels by 5% to 10% (1,2). Statins also reduce cardiovascular and overall mortality by...
Pannorin, a naphthopyrone that inhibits 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol synthesis, was isolated from a culture broth of Chrysosporium pannorum M10539 by solvent extraction, Bio-Gel P-6 column chromatography and reverse phase HPLC (Silica ODS). Spectroscopic analyses of the compound yielded 4,8,10-trihydroxy-5-methyl-2H-naphtho[1...
Component A, the oxygen-sensitive protein fraction of the methyl coenzyme M methylreductase system of Methanobacterium thermoautotrophicum, has been stabilized and resolved into three protein fractions and one cofactor that are required to reconstitute component A activity. Component A1 is oxygen-stable and contains hydrogen-dependent deazaflavin (coenzyme F420)-reducing activity. Component A2 ...
The terminal enzyme of the NADH-dependent stearyl coenzyme A desaturase system has been isolated from rat liver microsomes. This desaturase is a single polypeptide of 53,000 daltons containing 62% nonpolar amino-acid residues and one atom of non-heme iron. The purified protein forms high molecular weight aggregates that can be dispersed by detergent procedures. Desaturase activity requires NADH...
Prevention of recurrent life-threatening arrhythmias: will lipid-lowering therapy make a difference?
There is a strong, positive, independent, continuous, graded relation between hypercholesterolemia and the risk for coronary heart disease (CAD). In clinical trials, it has been shown that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors or statins inhibit HMGCoA reductase competitively, reduce LDL levels more than other cholesterol-lowering drugs and lower triglyceride leve...
Methyl-coenzyme M reductase (MCR) is the key enzyme of methanogenesis and anaerobic methane oxidation. The activity of MCR is dependent on the unique nickel-containing tetrapyrrole known as coenzyme F430. We used comparative genomics to identify the coenzyme F430 biosynthesis (cfb) genes and characterized the encoded enzymes from Methanosarcina acetivorans C2A. The pathway involves nickelochela...
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