Reduced by deoxyhemoglobin to form nitric oxide. Nitrite is also reduced to nitric oxide and further reduced to ammonia by gut bacteria. Nitrite can be oxidized to nitrate by oxyhemoglobin.
The reactions of nitrogen dioxide with cyclohexene have been studied as a model for the reactions that occur between nitrogen dioxide in smoggy air and unsaturated fatty acids in pulmonary lipids. As predicted from earlier studies at high nitrogen dioxide concentrations, this gas reacts with cyclohexene predominantly by addition to the double bond at nitrogen dioxide concentrations of 1 percent (10,000 parts per million) to 40 percent in nitrogen; in the presence of air or oxygen, this reaction initiates the autoxidation of the alkene. However, at concentrations below 100 parts per million in nitrogen, nitrogen dioxide reacts with cyclohexene almost exclusively by abstraction of allylic hydrogen; this unexpected reaction also initiates the autoxidation of the alkene in the presence of oxygen or air, but it leads to the production of nitrous acid rather than of a product containing a nitro group attached to a carbon atom. The nitrous acid can react with amines to produce nitrosamines. Moreover, the nitrite ion produced by the hydrogen abstraction mechanism would be expected to diffuse throughout the body, unlike nitrated lipids that would be confined to the pulmonary cavity. These findings have been confirmed with methyl oleate, linoleate, and linolenate; some of the kinetic features of the nitrogen dioxide-initiated autoxidation of these unsaturated fatty acids have been studied. .
来源:Hazardous Substances Data Bank (HSDB)
代谢
亚硝酸盐及其代谢物通过尿液排出体外。
Nitrites and their metabolites are excreted in the urine. (L1137)
Nitrite causes the autocatalytic oxidation of oxyhemoglobin to hydrogen peroxide and methemoglobin. This elevation of methemoglobin levels is a condition known as methemoglobinemia, and is characterized by tissue hypoxia, as methemoglobin cannot bind oxygen. (A2450, L1613)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌物分类
摄入硝酸盐或亚硝酸盐,在导致内源性亚硝化的条件下,可能对人类具有致癌性(2A组)。
Ingested nitrate or nitrite under conditions that result in endogenous nitrosation is probably carcinogenic to humans (Group 2A). (L135)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
健康影响
亚硝酸盐中毒导致高铁血红蛋白血症。亚硝酸盐可能导致怀孕并发症和发育影响。它们也可能具有致癌性。
Nitrite poisoning causes methemoglobinemia. Nitrites may cause pregnancy complications and developmental effects. They may also be carcinogenic. (L1137)
Nitrite poisoning causes methemoglobinemia. Symptoms include cyanosis, cardiac dysrhythmias and circulatory failure, and progressive central nervous system (CNS) effects. CNS effects can range from mild dizziness and lethargy to coma and convulsions. (L1137)
Reactive nitrogen species derived from nitric oxide are potent oxidants formed during inflammation that can oxidize membrane and lipoprotein lipids in vivo. ... Several of these species react with unsaturated fatty acid to yield nitrated oxidation products. ... Reaction of HPODE, but not linoleate, with nitrous acid (HONO) or isobutyl nitrite (BuiONO) yielded a product at m/z 340, or 341 upon reacting with [15N]HONO. MS/MS analysis gave an NO2- fragment, and 15N NMR indicated that the product contained a nitro (RNO2) functional group, suggesting that the product was nitroepoxylinoleic acid [L(O)NO2]. This species could form via homolytic dissociation of LOONO to LO* and *NO2 and rearrangement of LO* to an epoxyallylic radical L(O)* followed by recombination of L(O)* with *NO2. Since unsaturated lipids of membranes and lipoproteins are critical targets of reactive oxygen and nitrogen species, these pathways lend insight into mechanisms for the formation of novel nitrogen-containing lipid products in vivo and provide synthetic strategies for further structural and functional studies.
THE REACTION OF NITROUS ACID WITH 4-SUBSTITUTED-THIOSEMICARBAZIDES
作者:Eugene Lieber、C. N. Pillai、Ralph D. Hites
DOI:10.1139/v57-116
日期:1957.8.1
degradation to an isothiocyanate and azide ion, and (2) isomerization to a 1-substituted-tetrazole-5-thiol, the extent of path (1) or (2) depending on the nature of the substituent. Path (1) predominates when the substituent is alkyl, whereas when the substituent is aryl both paths (1) and (2) occur, the relative proportion depending on the electrical nature of the aromatic group, path (2) increasing as the
the kinetic data enabled extraction of the bimolecular rate constants, kNO+ = (3.2 ± 1.8) × 1010 M−1 s−1; kNOSCN = (2.1 ± 0.2) × 105 M−1 s−1; kNOBr = (9.4 ± 0.2) × 106 M−1 s1 and kNOCl = (4.0 ± 0.2) × 107 M−1 s−1, for the pathways catalyzed by SCN−, Br− and Cl−, respectively. Kinetic results are consistent with the attack on the nitrosating agent as the rate limiting step, i.e., the nitrosation of FDS
酸亚硝化的反应动力学。 二am甲am (FDS)显示出自催化行为,这是由于以下事实引起的: 硫氰酸盐 作为产品形成的离子起着强大的作用 催化剂用于亚硝化反应。在存在添加的亲核试剂的情况下,自催化途径的抑制是由于添加的亲核试剂之间的亚硝酸竞争而产生的。卤化物 和 硫氰酸盐阴离子,作为反应产物形成。分析动力学数据萃取双分子速率常数k NO +=(3.2±1.8)×10 10 M -1 s -1;k NOSCN =(2.1±0.2)×10 5 M -1 s -1 ; ķ NOBR =(9.4±0.2)×10 6中号-1小号1和ķ NOCl =(4.0±0.2)×10 7中号-1小号-1,对于由SCN催化的途径-,溴-和Cl -, 分别。动力学结果与速率限制步骤对亚硝化剂的攻击是一致的,即FDS的亚硝化行为与亚硝基化剂的亚硝化行为相似。胺。对于其他具有以下特性的基材,发现的行为却有所不同。亚米诺 与
Synthesis of Copper and Lithium Copper Ferrites as High Magnetization Materials
作者:K. E. Kuehn、D. Sriram、S. S. Bayya、J. J. Simmins、R. L. Snyder
DOI:10.1557/jmr.2000.0235
日期:2000.7
The ferrite with composition Cu0.5Fe2.5O4 was heat treated in air and in reducing atmospheres to different temperatures within the solid solution region confirmed by dynamic high-temperautre x-ray characterization. The samples were quenched in oil and air, and lattice parameter, Curie temperature, and saturation magnetization measurements were completed. The magnetization measurements for these samples showed a maximum 4πMs of 0.7729 and 0.5426 T at 10 and 300 K, respectively. The cationic distribution based on the low-temperature 4πMs measurements is (Cu+0.24Fe3+0.76)A[Cu+0.26Fe3+1.74]BO4 → 4.9 µ B. X-ray-pure Cu0.5Fe2.5O4 samples were also synthesized by slow cooling from the formation temperature to 900 °C in a reducing atmosphere. A temperature–PO2 diagram for the stability of Cu0.5Fe2.5O4 under the conditions of the experiment was determined. Low-temperature 4πMs measurements did not indicate an increase in the Cu+ A site occupancy for the samples cooled to 900 °C in a reducing environment above those samples that were quenched from high temperature. Curie temperatures for all Cu0.5Fe2.5O4 samples ranged from 348 to 369 °C. Lithium additions (0.1 mol/unit formula) to copper ferrite Li0.1Cu0.4Fe2.5O4 decreased the room-temperature 4πMs values to 0.5234 T with a corresponding decrease in the 10 K measurements to 0.7047 T. From the low-temperature magnetization measurements, the distribution was (Cu+0.15Fe3+0.85)A[Cu+0.25Li+0.1Fe3+1.65]BO4 → 4.48 µ B.
Accurate Rate Constants for Decomposition of Aqueous Nitrous Acid
作者:Mark S. Rayson、John C. Mackie、Eric M. Kennedy、Bogdan Z. Dlugogorski
DOI:10.1021/ic202081z
日期:2012.2.20
Decomposition of nitrous acid in aqueous solution has been studied by stopped flow spectrophotometry to resolve discrepancies in literature values for the rate constants of the decomposition reactions. Under the conditions employed, the rate-limiting reaction step comprises the hydrolysis of NO2. A simplified rate law based on the known elementary reaction mechanism provides an excellent fit to the
已经通过停止流动分光光度法研究了亚硝酸在水溶液中的分解,以解决分解反应速率常数的文献值差异。在所采用的条件下,限速反应步骤包括NO 2的水解。基于已知基本反应机理的简化速率定律非常适合实验数据。速率常数1.34×10 –6 M –1 s –1由于不依赖于平行反应路径的速率或气态反应产物的相间传质的速率,因此,据认为该方法比文献中的具有更高的准确度。简化速率定律的活化能被确定为107 kJ mol –1。量子化学计算表明,大多数从平衡2HNO的吸热性质的大的活化能结果的2 ⇆NO + NO 2 + H 2 O.速率常数为硝酸根离子和亚硝酸的反应,从而抑制HNO 2分解,也被确定。
The electrochemical studies of cytochrome c incorporated in 3D porous calcium alginate films on glassy carbon electrodes
作者:Shan Jian、Xingchao Liu、Hong Sun、Shifeng Hou
DOI:10.1039/c3ra45801f
日期:——
In this work, the cytochrome c (Cyt c) was incorporated in three-dimension (3D) porous calcium alginate (CA) films prepared by using sodium alginate, calcium chloride and polyethylene glycol, and formed the electroactive porous Cyt c–CA composite films. The stable composite films were characterized by means of scanning electron microscopy (SEM), UV-vis absorption, cyclic voltammetry (CV) and square-wave voltammetry (SWV) techniques. UV-vis experiments demonstrated that Cyt c assembled in the 3D porous CA films retains its near native conformation at medium pH. The Cyt c–CA films modified on glassy carbon electrodes showed a pair of well-defined and nearly reversible cyclic voltammetry peaks at about −0.352 V vs. SCE in protein-free buffer, which originated from heme FeIII/II redox couples within Cyt c. The electrochemical parameters such as apparent heterogeneous electron transfer rate constant (ks) and formal potential (Eo’) were estimated by fitting the data of SWV with nonlinear regression analysis. The Cyt c–CA films showed the electrocatalytic activity toward dioxygen, hydrogen peroxide, nitrite and trichloroacetic acid with significant decreases in the electrode potential required. Experimental data demonstrated that the porous film can provide a favorable microenvironment for the protein to directly transfer electrons with the underlying electrode and possess good stability and reproducibility, showing the possible future application of the films for biosensors and biocatalysis.