问题：很奇怪的几个短语
类型：求助 (悬赏分:3分)
提问：ljwb123456
等级：▲
版块：高分子科学(kevlar,wmx,lby010,)
信誉：81%
回复：2
阅读：3101
时间：2007-05-03 09:39:14 编辑加入/取消收藏订制/取消短消息举报该贴

有人知道这几个专业词汇的意思吗? water-structuring salt, kosmotropic salt谢谢侬!

回复人：tangyyer,★★★★★ (有空来逛逛my blog: http://tangyyer.blog.hexun.com) 时间：2007-05-05 10:35:33 编辑

1楼

water-structuring salt, kosmotropic salt着两个是相同的意思。

kosmotropes一般和chaotropes是相对的。
The terms 'kosmotrope' (order-maker) and 'chaotrope' (disorder-maker) originally denoted solutes that stabilized, or destabilized respectively, proteins and membranes.何谓『kosmotrope』(秩序制造者)'chaotrope』(紊乱制造者),原本指溶质稳定或不稳定,而膜蛋白. Later they referred to the apparently correlating property of increasing, or decreasing respectively, the structuring of water.后来他们所指的相关性明显增加,或减少,分别组建了水. Although useful, the terminology may sometimes be misleading as such properties may vary dependent on the circumstances, method of determination or the solvation shell(s) investigated.虽然有用,有时会误导,因为这类术语可能各有特性依赖的情况下,溶剂法测定或壳牌(S)已查处. For example a solute may not always act in the same way at different concentrations or in the presence of macromolecules or gels [ 276 ].比如一种溶质不一定采取同样的方式,在不同浓度或驻留大分子或凝胶[276]. Also some solutes with less well-defined properties ( e.g.还有些溶质与较差的定义属性(例如 urea) are sometimes classified as kosmotropes [ 276 ] and sometimes as chaotropes [ 283 ].尿素)有时列为kosmotropes〔276〕,时而chaotropes〔283〕. An alternative term used for kosmotrope is 'compensatory solute' as they have been found to compensate for the deleterious effects of high salt contents (which destroy the natural hydrogen bonded network of water) in osmotically stressed cells, but again behavior as a kosmotrope in one system does not mean that a solute may behave as a 'compensatory solute' in another or even that it will stabilize the structuring of water in a third.另类术语,用以kosmotrope是'补偿性溶质',因为他们已经发现,以弥补因有害影响.高盐含量 (破坏自然的氢键网络的水),在osmotically强调细胞但同样的行为作为kosmotrope在一个系统并不意味着溶质可能像一个'补偿性溶质的另一个甚至认为它会稳定的结构水的三分之一. Both the extent and strength of hydrogen bonding may be changed independently by the solute but either of these may be, and has been, used as measures of order making.无论程度和强度氢键独立可以改变,但无论这些溶质可以,一直作为对策,以便制作. It is, however, the effects on the extent of quality hydrogen bonding that is of overriding importance as true kosmotropes shift the local但令人影响程度的质量氢键,这是压倒一切的重要性,真正把kosmotropes地方
le ss dense water ( e.g. less密水(例如 ES )es) reversible arrow more dense water ( e.g.更为稠密水(例如 CS )政务)
equilibrium to the left and chaotropes shift it to the right.为了平衡左右chaotropes转移给权利. The ordering effects of kosmotropes may be confused by their diffusional rotation, which creates more extensive disorganized junction zones of greater disorder with the surrounding bulk water than less hydrated chaotropes.订购kosmotropes效应扩散可能迷惑了轮换更广泛地区造成更大的混乱无序路口与周围的水比散装水合chaotropes少. It seems clear that most kosmotropes do not cause a large scale net structuring in water [ 595 ].看来很明显,最kosmotropes不会造成大规模的网络结构水〔595〕.

Ionic kosmotropes a should be treated differently from non-ionic kosmotropes, due mainly to the directed and polarized arrangements of the surrounding water molecules.离子kosmotropes一应有别于非离子kosmotropes,主要原因在于导演和周围的水分子的两极安排. Generally, ionic behavior parallels the Hofmeister series .一般而言,行为就像碘离子系列. Large singly charged ions, with low charge density ( e.g.大型singlychargedions,低电荷密度(例如 SCN - , H 2 PO 4 - , HSO 4 - , HCO 3 - , I - , Cl - , NO 3 - , NH 4 + , Cs + , K + , (NH 2 ) 3 C + (guanidinium) and (CH 3 ) 4 N + (tetramethylammonium) ions; exhibiting weaker interactions with water than water with itself and thus interfering little in the hydrogen bonding of the surrounding water), are chaotropes whereas small or multiply-charged ions, with high charge density, are kosmotropes ( e.g.营养、二月八宝4、高速输出单元HSO4-、小贩3-我-、氯、无三、铵4+,+政务、钾、丙(铵2)3+(胍的CH)及(3)4+氮离子(四甲基);exhibiting弱相互作用与水比水自己,从而干扰少的氢键周边水),是chaotropes而小或乘带电离子,高电荷密度,有kosmotropes(例如 SO 4 2- , HPO 4 2- , Mg 2+ , Ca 2+ , Li + , Na + , H + , OH - and HPO 4 2- , exhibiting stronger interactions with water molecules than water with itself and therefore capable of breaking water-water hydrogen bonds).所以42-,HPO的42-、2+毫克钙2+、锂离子、钠离子、氢离子哦-磷酸42-、展现更强的互动与水分子比水本身能破水,所以水氢键). b The radii of singly charged chaotropic ions are greater than 1.06Å for cations and greater than 1.78Å for anions [ 284 ].二落单的chaotropic离子半径大于阳离子和1.06å供大于1.78å为阴离子[284. Thus the hydrogen bonding between water molecules is more broken in the immediate vicinity of ionic kosmotropes than ionic chaotropes.因此水分子之间的氢键更打破了附近的离子kosmotropes比chaotropes离子. Reinforcing this conclusion, a Raman spectroscopic study of the hydrogen-bonded structure of water around the halide ions F - , Cl - , Br - and I - indicates that the total extent of aqueous hydrogen bonding increases with increasing ionic size [ 685 ] and an IR study in HDO:D 2 O showed slow hydrogen bond reorientation around these halide ions getting slower with respect to increasing size [8 95 ].这一结论加强了拉曼光谱研究的氢键结构卤化物离子水周围歼、氯、溴、中级标志着总程度而增加离子水氢键规模〔685〕、红外学习镇区:丁2O的氢键调整缓慢表明围绕这些卤化物离子越慢就日益庞大[895]. It is not unreasonable that a solute may strengthen some of the hydrogen bonds surrounding it (structure making; e.g.这并非是不合理的,一种溶质可能加强部分的氢键围绕着它(结构制作;例如: kosmotropic cations will strengthen the hydrogen bonds donated by the inner shell water molecules) whilst at the same time breaking some other hydrogen bonds (structure breaker; e.g.kosmotropiccations将加强氢键捐赠的内壳,水分子),同时打破其他一些氢键(断路器结构;例如: kosmotropic cations will weaken the hydrogen bonds accepted by the inner shell water molecules) [ 274 ], so adding to the confusion in nomenclature.kosmotropic阳离子也会削弱氢键水分子接受党内壳牌)[274]所以在名称上加乱. Other factors being equal, water molecules are held more strongly by molecules with a net charge than by molecules with no net charge; as shown by the difference between zwitterionic and cationic amino acids [ 532 ].其他因素不变,水的分子与分子进行更强烈的净电荷的分子比无净电荷;列之间的差别zwitterionic阳离子氨基酸[532].

Weakly hydrated ions (chaotropes, K + , Rb + , Cs + , Br - , I - , guanidinium + ) may be 'pushed' onto weakly hydrated surfaces by strong water-water interactions with the transition from strong ionic hydration to weak ionic hydration occurring where the strength of the ion-water hydration approximately equals the strength of water-water interactions in bulk solution (with Na + being borderline on the strong side and Cl - being borderline on the weak side) [ 284 ].水合离子弱(chaotropes、钾、铷+、+政务、溴、中级、胍+)可能是'推'到弱hydratedsurfaces强烈水水互动与转型,从强离子水合弱水化那里发生的实力离子水水化约合实力水水互动散装解(与Na+是胜败的强者和Cl-是胜败的弱者)[284]. Neutron diffraction studies on two important chaotropes (guanidinium and thiocyanate ions) show their very poor hydration, supporting the suggestion that they preferentially interact with the protein rather than the water [ 488 ].中子衍射研究两个重要chaotropes(硫氰酸胍和离子)出示极差水化,他们建议,优先支持与蛋白质相互作用而非水〔488〕. In contract to the kosmotropes, there is little significant difference between the properties of ionic and nonionc chaotropes due to the low charge density of the former. 合同的kosmotropes,有多大区别的性能和离子nonioncchaotropes由于低电荷密度前者. to top of page

Optimum stabilization of biological macromolecule by salt requires a mixture of a kosmotropic anion with a chaotropic cation.最佳镇定生物大分子的混合盐需要一个具有阴离子chaotropickosmotropic阳离子. As ionic kosmotropes primarily achieve their increased structuring solely within their hydration shell, they partition into the more dense ( CS ) water where they can obtain this hydration water more readily, whereas the ionic chaotropes, by avoiding interference with water's hydrogen-bonded network, tend to clathrate formation within the less dense ( ES ) environment.作为实现其主要离子kosmotropes只靠增加其水化壳结构,划分成更密集(政务)水何处可以获得这样更容易水化水,而chaotropes离子、避免干扰水的氢键网络,往往形成包合物的环境较稠密(权证). Thus there is agreement with the defining characteristic of an ionic chaotrope in that it partitions selectively into low-density water whereas a kosmotrope partitions selectively into high-density water [ 276 ].因此,协议的决定性特征离子chaotrope,它间隔成选择性低密度水而kosmotropepartitions选择性分为高密度水[276]. The stabilizing of structured low-density water (by ionic chaotropes) in turn stabilizes the hydration shell around lower molecular weight hydrophobes, as seen in the promoted association of polyene antibiotics by ionic kosmotropes and the stabilization of their solution by ionic chaotropes [ 1030 ]. 稳定结构的低密度水(离子chaotropes)从而使得周围低分子量hydrophobes水化壳、正如该协会提倡多烯抗生素离子kosmotropes和稳定其溶液离子chaotropes〔1030〕.

Non-ionic kosmotropes are very soluble well-hydrated molecules with little tendency to aggregate, having no net charge and strongly hydrogen bonding to water, that stabilize the structure of macromolecules in solution.非离子水溶性kosmotropes非常好水合分子倾向总量不大、无净电荷,强烈氢键水,大分子结构,稳定溶液. They are preferentially solubilized within the bulk of the solution and excluded from the solvation layers of macromolecular surfaces.他们大部分在优先溶解、排除溶剂高分子表面层. Consequentially, they decrease the water diffusion around the proteins and the exchange rate of backbone amide protons [ 621 ].因而,减少蛋白质和水扩散周围汇率骨干酰胺质子〔621〕. This leads to the dehydration of such surfaces and ensures that they are less flexible and therefore more thermally stable but less enzymatically active.这导致脱水,这样的表面,并确保他们都不太灵活,因此更热稳定少enzymatically活跃. c Kosmotropes reduce the volume of water available to hydrate the larger surface exposed by denatured proteins, so tending to prevent the denaturation process (the 'excluded volume' effect).These kosmotropes may be divided into two groups which act somewhat differently: (1) polyhydroxy compounds fit in well with the hydrogen bonding arrangements, but stabilize any cluster 'flickering' via hydrogen bond rearrangement, as their hydroxyl groups are similarly separated to water-water separations (see sugar hydration ), and (2) zwitterions where the balance between hydrophilicity, hydrophobicity, anionic and cationic characteristics ensures good solubility but only weak net interactions to surrounding water.三kosmotropes 缩小体积水能水合物较大的暴露表面的蛋白质,这样的倾向,防止变性进程('排斥体积的效应).这些kosmotropes可分为两个群体行为稍有不同: (1)多羟基化合物符合了氢键安排但任何稳定集束'摇曳'经由氢键重排,由于其羟基同样隔开水水离职(见糖水化),(2)氨基酸的平衡,亲水性,疏水性,阴离子和阳离子特色ensures溶解性好,但只有弱相互作用网,对周围的水.

Chaotropes break down the hydrogen-bonded network of water, so allowing macromolecules more structural freedom and encouraging protein extension and denaturation.chaotropes打破氢键网水,因此允许大分子结构更加自由,鼓励推广和蛋白质变性. Kosmotropes are stabilizing solutes which increase the order of water (such as polyhydric alcohols [ 307 ], trehalose, trimethylamine N -oxide, glycine betaine, ectoine, proline and various other zwitterions) whereas chaotropes create weaker hydrogen bonding, decreasing the order of water, increasing its surface tension (but see anomaly ) and destabilizing macromolecular structures (such as guanidinium chloride and urea at high concentrations).这是稳定增长kosmotropes溶质水秩序(如多元醇〔307〕、海藻糖、甲胺氮氧化物、甜菜碱、ectoine,脯氨酸和其他各种盐)而创造chaotropes氢键较弱,为了减少用水,增加其表面张力(但看到异常)和大分子结构不稳定(如尿素、高浓度氯胍). Urea only strongly hydrogen bonds to about two water molecules; otherwise it can hydrogen bond to itself or water with close to equal ease making only a poor structure-breaker (chaotrope) over much of its concentration range [ 1171 ].尿素只有极力氢键约两个水分子;否则可以氢键本身或水接近平等缓和只是在一个贫穷的结构夹克(chaotrope)远超过其浓度〔1171〕. It can fit into a tetrahedral water network and shows little preference between ES -like and CS -like water clusters [ 1171 ].它可以纳入一个四面体水网,几乎是偏好之间es式和CS-像水簇〔1171〕. Other work has shown that urea weakens both hydrogen bonding and hydrophobic interactions but glucose acts as a kosmotrope, enhancing these properties [ 283 ].其他工作已表明,尿素削弱双方氢键和疏水但葡萄糖作为kosmotrope,这些增强性能[283]. The idiosyncratic behavior of urea may well be due to its concentration-dependent oligomerization; cyclic hydrogen-bonding dimers and oligomers behaving differently from monomers [ 364 ].奇特的行为可能是由于尿素的浓度依赖齐聚;环状氢键二聚体和寡聚behavingdifferentlyfrommonomers[364]. Thus, when urea molecules are less than optimally hydrated (about 6 - 8 moles water per mole urea) urea hydrogen bonds to itself and the protein (significantly involving the peptide links [ 528 ]) in the absence of sufficient water, so becoming more hydrophobic and hence more able to interact with further sites on the protein, leading to localized dehydration-led denaturation.因此,当尿素分子少于optimallyhydrated(约6-8胎,每水摩尔尿素)尿素的氢键本身和蛋白质(明显涉及多肽连接[528]),在没有足够的水,所以变得更加疏水,因此较能与更多站点的蛋白质,导致局部脱水导致变性. Guanidinium is a planar ion that may form weak hydrogen bonds around its edge but may establish strongly-held hydrogen-bonded ion pairs to protein carboxylates, similar to commonly found quaternary structural arginine-carboxylate 'salt' links.guanidinium是一个平面离子可形成弱氢键围绕自己的优势,但可能树立强烈召开氢键离子对蛋白质的羧酸,类似通常发现第四纪结构精氨酸carboxylate'盐'三通. Also, guanidinium possesses rather hydrophobic surfaces that may interact with similar protein surfaces to enable protein denaturation [ 571 ].同时,guanidinium拥有相当的疏水表面相互作用,可能具有类似的表面蛋白,使蛋白质变性[571]. Both denaturants may cause protein swelling and destructuring by sliding between hydrophobic sites and consequently dragging in hydrogen-bound water to complete the denaturation.双方可变性蛋白质引起肿胀和destructuring由之间滑动疏水性用地,因此拖在氢束缚水完整的变性.

Rather unexpectedly, whereas L-amino acids and D-glucose prefer a less dense ( ES ) environment, D-amino acids and L-glucose prefer more dense ( CS ) water [ 574 ]; a consequence of which may be that condensed polymers of the former (rather than their optical isomers) may have formed in primordial clays so setting the trend for the molecular evolution [ 374 ].比较意外的是,虽然左旋氨基酸、葡萄糖宁愿少密(权证)环境D型氨基酸及L-葡萄糖更希望浓(2)水〔574〕;其后果可能是聚合物凝聚态的前(而非其光学异构物),可能形成在原始粘土所以设置趋势进行了分子演化[374]. Although the arrangement of oxygen atoms within water clusters may be symmetrical, the energetic preference for particular hydrogen-bonding arrangements ensures the necessary chirality. 虽然安排在水中氧原子簇可对称,充满活力的偏好,特别是氢键安排,保证必要的手. to top of page

Kosmotropeskosmotropes

a Trimethylamine N -oxide一甲胺氮氧化物

b Proline二脯氨酸

c Ectoine; R varying三ectoine;住宅变

d α,α-Trehalose丁α,α-海藻糖

e Glycine betaine电子甜菜碱

f 3-Dimethylsulfoniopropionate六3-中DMSP

a Trimethylamine N-oxide;b Proline;c Ectoine; R varying;d alpha,alpha-Trehalose;e Glycine betaine;f 3-Dimethylsulfoniopropionate

Generally the kosmotropic/chaotropic nature of a solute is determined from the physical bulk properties of water, often at necessarily high concentration.一般来说kosmotropic/chaotropic溶质的性质决定了从物理性能散装水常常在一定浓度偏高. The change in the degree of structuring may be found, for example, using NMR ([ 307 ]) or vibrational spectroscopy .结构变化的程度可以发现,例如,使用核磁共振(〔307〕)或振动光谱. Protein-stabilizing solutes (kosmotropes) increase the extent of hydrogen bonding (reducing the proton and 17 O spin-lattice relaxation times ) whereas the NMR chemical shift may increase (showing weaker bonding e.g.蛋白质溶质稳定增长幅度(kosmotropes)氢键(减质子和17澳自旋晶格弛豫时间),而化学位移可能增加(表现较弱的键例如 the zwitterionic kosmotrope, trimethylamine N-oxide) or decrease (showing stronger bonding e.g.kosmotrope的两性离子、甲胺氮氧化物)或下降(例如呈现较强粘接 the polyhydroxy kosmotrope, trehalose).<聚kosmotrope,海藻糖). Trehalose shows both a reduction in chemical shift and relaxation time, as to a lesser extent does the protein stabilizer (NH 4 ) 2 SO 4 , whereas NaCl only shows a reduction in chemical shift and the protein destabilizer KSCN shows an increase in relaxation time and a reduction in chemical shift (note these NMR parameters are both time and structurally averaged values, where the weighting of the averaging is unclear) [ 281 ].海藻糖表明双方削减化学位移和松弛时作为一个较小的程度是否稳定蛋白(nh4)24等,而氯化钠只显示减少化学位移与蛋白质destabilizerkscn有所增加松弛时间并减少化学位移(注核磁共振这些参数都是时间上和结构上的平均价值,那里的加权平均不清)〔281〕. Vibrational spectroscopy may make use of the near-IR wavelength near 5200 cm -1 ( v 2 + v 3 combination ), which shifts towards longer wavelength (smaller wavenumber) when hydrogen bonds are stronger [ 282 ].可利用振动光谱近红外波长接近5200年公分-1(五2+结合三月五),转向波长较长时(少波)氢键强〔282〕. It should be noted however that ranking of kosmotropic/chaotropic character by different measures show inconsistencies.不过,也应注意到,排名kosmotropic/chaotropic性格不同的措施,显示的不一致.

One of the most important kosmotropes is the non-reducing sugar α,α-trehalose.其中最重要的是kosmotropes非还原糖α,α-海藻糖. It should perhaps be noted that trehalose has a much more static structure than the reducing sugars, due to its lack of mutarotation, or the other common non-reducing disaccharide, sucrose, due to its lack of a furan ring .它也许应当指出海藻糖具有更比还原糖静态结构,缺乏变旋,或其他常见的非减糖、蔗糖、缺乏一个呋喃环. Both Inelastic neutron scattering [ 543 ] and 17 O-NMR show that a rotational restriction exists in trehalose-bound water, indicating that trehalose is definitely a net water-structurer.无论弹性中子散射〔543〕和17邻核磁共振显示轮换限制存在海藻糖行水显示海藻糖绝对净水structurer. These stronger interactions d (between the trehalose and water compared to water-water interactions) increase the bioprotective effectiveness of trehalose [ 887 ] by reducing the (re-)activity of the water molecules.这些强大的互动丁(海藻糖之间相比,用水节水用水互动)增加bioprotective成效海藻糖[887]减(重)活性的水分子. Trehalose interferes with the tetrahedral network of water, structuring out to at least the third solvation layer, in such a way as to reduce the amount of freezable water [ 285 ].海藻糖干扰了四面体网供水,构建出至少三次溶剂层这种做法,减少用水数量冻结〔285〕. This is consistent with an increase in the local structuring, due in part to maximizing the number of singly hydrogen-bonded water molecules (to trehalose) without any (trehalose) intramolecular hydrogen bonds or oriented water mol ecules held by two (trehalose) hydrogen bonds.这符合当地增加编制、部分原因是为了最大限度地增加单机氢键水分子(海藻糖),无(海藻糖)intramolecular氢键或面向水molecules举行两次(海藻糖)氢键. There is also reduced tetrahedrality amongst the associated water molecules [ 660 ].还有tetrahedrality降低水分子之间的联系〔660〕. At lower water contents, essentially all the water is associated with single hydrogen bonds to trehalose or first shell water with consequential reduction in the ability to form four hydrogen bonds per water molecule but retaining an expanded structure.含水量较低,基本上所有的水是与单一的氢键海藻糖或第一轮壳水相应减少能否形成四氢键,每个水分子但保留一个扩大结构. Trehalose is particularly effective at stabilizing macromolecules as it has a large hydrated volume (2.5 times that of sucrose, indicating that there is less water for the same volume; i.e. low-density water is present) [ 279 ].海藻糖是特别有效,因为它是稳定大分子水合量大(2.5倍蔗糖、显示有相同数量少用水;即低密度水是当前)[279]. Trehalose can also protect membranes in anhydrobiosis by hydrogen bonding directly to the phosphate groups in the phospholipids at low water content, so spreading their head groups and reducing the membrane's tendency to undergo phase transitions and thus leak during rehydration [ 308 ].海藻糖也可以保护膜anhydrobiosis氢键直接磷酸盐集团卵磷脂低含水量组组长等蔓延和减少其细胞膜的相变而倾向接受期间泄漏体液[308. As a further protective action trehalose crystals, formed at low water content, can lose (and regain) up to two molecules of water per molecule without changing their crystal structure or volume [ 327 ].为进一步保护行动海藻糖晶体,形成低水分、可失去(重获)最多两个分子水分子每不改变其晶体结构或体积[327].

Temperature and pressure both have effects on the kosmotropic/chaotropic status with the effects disappearing at high temperatures, particularly at high concentrations [ 1170 ].温度和压力都对kosmotropic/chaotropic地位与作用消失,在高温下,特别是在高浓度〔1170〕. For example, at very high pressures (0.6 GPa) Na + ions change from being weak kosmotropes into weak chaotropes as their links to water molecules are preferably broken [ 1170 ].举例来说,在非常高的压力(0.6gpa)钠离子转变,由弱到kosmotropeschaotropes薄弱的环节水分子最好断〔1170〕. to top of page

a Perhaps ionic kosmotropes should be called antichaotropes to distinguish them from non-ionic kosmotropes.一个也许离子kosmotropes应该叫antichaotropes有别于非离子kosmotropes.

回复人：ljwb123456,▲ () 时间：2007-06-21 09:32:23 编辑	2楼
已经打分了。

得分人：tangyyer：2,

问题讨论没有结束...

您尚未进入本论坛,登录之后才可以回贴

9msec