Oxidation

Đây là bài giảng của thầy Đỗ Hiếu Liêm, trường ĐH Nông Lâm TP.HCM. Chuỗi hô hấp mô bào bao gồm các phản ứng oxid hoá khử liên tục trên các cơ chất (sản phẫm biến dưỡngtrung gian - Chu trình Krebs và β oxid hoá acid béo). Tổ chức: hệthống enzyme CHH với các coenzyme tổchức thành từng tổ hợp và sắp xếp theo thứ tự tăng dầnđiện thế oxid hoá khử,bắđầu NAD+ dehydrogenase có điện thế âm và cuối cùng là cytochrome oxidase có điện thế dương....

32p h08112107 22-08-2010 250 131   Download

Catalytic oxidation of organic compounds is an extremely important field of chemistry, spanning the range from biological oxidations to large scale industrial production of commodity chemicals. However, many of these transformations can hardly be classified as organometallic reactions, since the catalysts (often simple metal salts) and the intermediates can be rather regarded as coordination complexes than organometallic compounds.

7p boyminsk 10-06-2010 75 18   Download

In order to meet the increasing demand for valve-regulated lead–acid ŽVRLA. batteries, a new soft lead has been produced by Pasminco Metals. In this material, bismuth is increased to a level that produces a significant improvement in battery cycle life. By contrast, other common impurities, such as arsenic, cobalt, chromium, nickel, antimony and tellurium, that are known to be harmful to VRLA batteries are controlled to very low levels. A bismuth ŽBi.-bearing oxide has been manufactured ŽBarton-pot method. ...

11p congdat261 19-11-2010 74 14   Download

For many years, the plates of leadracid batteries have been produced from leady oxide, a mixture of finely divided lead Ž‘free-lead’. and lead monoxide. Although this material is generally satisfactory, it suffers from the disadvantages that it is variable in composition and requires complicated and lengthy processing after pasting to remove the residual free-lead. Plates made from leady oxide also require cycling before they achieve their full performance, and this can result in either depressed initial capacity or additional processing cost. ...

4p congdat261 19-11-2010 49 7   Download

Mục đích của chúng tôi là khảo sát ảnh hưởng nồng độ tiền chất vào kích thước và tính chất từ của các hạt nano oxide sắt từ Fe3O4 bằng phương pháp đồng kết tủa. Chúng tôi nhận thấy rằng kích thước tinh thể và từ tính của các hạt gần như không phụ thuộc vào sự thay đổi hệ số đương lượng, và nồng độ các muối sắt ban đầu.

9p sunshine_7 22-07-2013 42 11   Download

Early metabolic steps, including glycolysis and the activity of the pyruvate dehydrogenase complex, yield a two-carbon fragment called an acetyl group, which is linked to a large cofactor known as coenzyme A (or CoA). It is during the citric acid cycle that acetyl-CoA is oxidized to the waste product, carbon dioxide, along with the reduction of the cofactors NAD+ and ubiquinone

94p zingzing09 21-10-2012 33 6   Download

The increased level of reactive oxygen species (ROS) in living organisms over 60 years ago was implicated in the development of diseases and aging (Harman, 1956; 1983). This book is a collective scientific monograph presenting several important aspects related to ROS role in human and animal pathologies. In 1985, German scientist Helmut Sies first denoted oxidative stress concept, which immediately attracted attention of researchers in diverse basic fields. Several discoveries substantially stimulated the interest to ROS as ones related to many diseases.

624p thienbinh1311 13-12-2012 63 3   Download

Clostridial glutamate dehydrogenase mutants, designed to accommodate the 2¢-phosphate of disfavoured NADPH, showed the expected large speci-ficity shifts with NAD(P)H. Puzzlingly, similar assays with oxidized cofac-tors initially revealed little improvement with NADP + , although rates with NAD + were markedly diminished.

9p cosis54 05-01-2013 20 3   Download

Polyamine oxidases are FAD-dependent enzymes catalyzing the oxidation of polyamines at the secondary amino groups.Zea maysPAO (ZmPAO) oxidizes the carbon on the endo-side of the N5-nitrogen of spermidine (Spd) and spermine (Spm).

13p mobifone23 07-01-2013 16 3   Download

The nitrite reductase activity of deoxyhemoglobin has received much recent interest because the nitric oxide produced in this reaction may participate in blood flow regulation during hypoxia. The present study used spectral deconvolution to characterize the reaction of nitrite with carp and rabbit hemoglobin at different constant oxygen tensions that generate the full range of physiological relevant oxygen saturations.

13p galaxyss3 07-03-2013 17 3   Download

The membrane lipid composition of planctomycetes capable of the an-aerobic oxidation of ammonium (anammox), i.e. Candidatus‘Brocadia anammoxidans’ and Candidatus‘Kuenenia stuttgartiensis’, was shown to be composed mainly of so-called ladderane lipids. These lipids are com-prised of three to five linearly concatenated cyclobutane moieties withcis ring junctions, which occurred as fatty acids, fatty alcohols, alkyl glycerol monoethers, dialkyl glycerol diethers and mixed glycerol ether⁄esters. ...

14p fptmusic 11-04-2013 31 4   Download

Almost 4000 years ago Egyptians and Babylonians used aluminum compounds in various chemicals and medicines. Herodotus mentioned alum in the fifth century b.c. and Pliny referred to “alumen,” now known as alum, as a mordant to fix dyes to textiles around 80 a.d. In 1754 Marggraf showed that a distinct compound existed in both alum and clays. In 1761 the French chemist Guyton de Morveau proposed the name “alumine” for the base in alum, identified in 1787 by Antoine Lavosier as the oxide of a then-undiscovered element.

40p dienthoi 09-05-2013 29 4   Download

Fatty acids (FAs) can be degraded via different mechanisms including a-, b- and x-oxidation. In humans, a range of different genetic diseases has been identified in which either mitochondrial FAb-oxidation, peroxisomal FAb-oxidation or FAa-oxidation is impaired. Treatment options for most of these disorders are limited.

13p mobifone23 07-01-2013 20 2   Download

Mitochondria are dynamic organelles that undergo continual fusion and fission to maintain their morphology and functions, but the mechanism involved is still not clear. Here, we investigated the effect of mitochondrial oxidative stress triggered by high-fluence low-power laser irradiation (HF-LPLI) on mitochondrial dynamics in human lung adenocarcinoma cells (ASTC-a-1) and African green monkey SV40-transformed kidney fibroblast cells (COS-7).

14p mobifone23 08-01-2013 22 2   Download

There is growing evidence that altered production and⁄or spatio-temporal distribution of reactive oxidant species and reactive nitrosative species in blood creates oxidative and⁄or nitrosative stresses in the failing myo-cardium and endothelium.

18p galaxyss3 21-03-2013 12 2   Download

Methemoglobin (metHb), an oxidized form of hemoglobin, is unable to bind and carry oxygen. Erythrocytes are continuously subjected to oxida-tive stress and nitrite exposure, which results in the spontaneous formation of metHb. To avoid the accumulation of metHb, reductive pathways medi-ated by cytochrome b5 or flavin,

10p galaxyss3 21-03-2013 13 2   Download

Thioredoxin reductase (TrxR) fromEscherichia coli,the mutant proteins E159Y and C138S, and the mutant protein C138Streated with phenylmercuric acetate were reconstituted with [U-13 C17 ,U-15 N4]FAD and analysed, in their oxidized and reduced states, by 13 C-, 15 N- and 31 P-NMR spectroscopy. The enzymes studied showed very similar 31 P-NMR spectra in the oxidized state, con-sisting of two peaks at )9.8 and )11.5 p.p.m. In the reduced state, the two peaks merge into one apparent peak (at)9.8 p.p.m.)....

16p dell39 03-04-2013 14 2   Download

Homocysteine (Hcy) is anonprotein-forming sulphur amino acid that plays an important role in remethylation and trans-sulphuration processes. In recent years, it has been suggested that increased levels of plasma Hcy may play a role in the pathogenesis of various diseases, particularly at the cardiovascular level. The pathogenic mechanism of hyperhomocysteinemia, however, has not been clarified.

6p dell39 03-04-2013 21 2   Download

In rat neuronal nitric oxide synthase, Phe1395 is positioned over the FAD isoalloxazine ring. This is replaced by Trp676 in human cytochrome P450 reductase, a tryptophan in related diflavin reductases (e.g. methionine synthase reduc-tase andnovel reductase 1), and tyrosine inplant ferredoxin-NADP + reductase. Trp676 in human cytochrome P450 reductase is conformationallymobile, andplays akey role in enzyme reduction. Mutagenesis of Trp676 to alanine results in a functional NADH-dependent reductase. ...

13p dell39 03-04-2013 10 2   Download

The effect of a-tocopheryl hemisuccinate (TS) on lipopolysaccharide (LPS)/interferon-c (IFN)-induced nitric oxide production in rat vascular smooth muscle cells (VSMC) was examined. The LPS/IFN-induced NO production was enhanced by TS but not by the other a-tocopherol (a-T) derivatives a-tocopheryl acetate (TA) and a-tocopheryl nicotinate (TN), or a-T itself. a-T, TA and TN inhibited the enhancement by TS of LPS/IFNinduced NO production.

6p research12 01-06-2013 19 2   Download