低浓度甲醛对多肽和蛋白化学修饰的质谱研究

采用基质辅助激光解析电离飞行时间质谱( MALDI-TOF MS)和纳升电喷雾四极杆飞行时间串联质谱( Nano-ESI -QTOF MS)技术,以标准肽段和流感病毒基质蛋白酶切肽段为模型,研究了甲醛对蛋白质和多肽主链的修饰作用。采用与实际病毒灭活过程一致的实验条件(4℃,0.025%(V/V)福尔马林(37%(w/w)甲醛溶液)处理72 h),进行甲醛与多肽的化学反应。结果表明,在实验条件下,甲醛能与标准肽段N端的氨基反应生成羟甲基加合物,再发生缩合反应生成亚胺,形成+12 Da的产物。此外,甲醛还能与标准肽段中的精氨酸、赖氨酸的侧链发生反应,生成+12 Da的反应产物。对流感病毒基质蛋白的酶切肽段与甲醛的反应的质谱分析结果显示,多数的肽段都生成了+24 Da的产物,质量的增加来源于肽段N端氨基(+12 Da)和C端精氨酸或赖氨酸的侧链(+12 Da)的贡献。此外,还观察到有一个漏切位点的肽段生成了+36 Da的产物。本研究结果表明,在实验条件下,低浓度甲醛主要与肽段和蛋白的N 端氨基,以及精氨酸和赖氨酸侧链发生反应。本研究为分析低浓度甲醛与蛋白质的反应产物提供了有效的质谱分析方法和解谱依据。     

聚乳酸-b-聚(N~ε-苄氧羰基-L-赖氨酸)-b-聚乙二醇的合成与表征

用端氨基聚乳酸做引发剂,在DMF中引发Nε-苄氧羰基-L-赖氨酸酐(Lys(Z)-NCA)聚合,合成了端氨基聚(Nε-苄氧羰基-L-赖氨酸)-b-聚乳酸两嵌段共聚物.以端羧基聚乙二醇经NHS活化与端氨基聚(Nε-苄氧羰基-L-赖氨酸)-b-聚乳酸偶联,合成了聚(乳酸-b-Nε-苄氧羰基-L-赖氨酸-b-乙二醇)三嵌段聚合物.利用IR、1H-NMR、GPC和TEM对它们的结构、形态进行了表征,结果表明,所合成的分子量可控、分子量分布窄(Mw/Mn=1.07)的嵌段共聚物,酰化反应产率达70%以上.同时聚乙二醇和Nε-苄氧羰基-L-赖氨酸被引入到聚乳酸主链中,在聚合物侧链脱保护后有望改善聚乳酸的细胞亲和性。     

血清多肽组及其个体差异的纳升液相色谱-高分辨串联质谱分析

分析和比较疾病组及健康对照组的混合样品是血清多肽组生物标记物研究的常用方法,但对健康个体多肽组的差异和共性关注较少.本研究利用纳升液相色谱-高分辨四级杆飞行时间质谱鉴定健康人混合血清样品(20例)的多肽组,阐明血清多肽组的分子量分布等一般特征,进而选取6例个体样品单独分析并与混合样品的分析结果进行比较,说明正常健康样品之间的个体差异和共同成分.结果表明,可鉴定序列的血清多肽组的分子量范围在7000 Da以下,纤维蛋白原α链等蛋白质所属肽段的检出频率最高,肽段在蛋白质水平上分布具有不均一性,排在前10％的蛋白质占据了约50％的总肽段,而后40％的蛋白质只有1条检出肽段.此外,在所有样品中都检测到了来自于8个蛋白质的12个共同肽段,检测到了N端乙酰化、氨基酸氧化、磷酸化、脱氨化和脱水等翻译后修饰和明显的阶梯序列现象.本研究在肽段序列水平分析了血清多肽组的基本特征和个体差异,可为血清多肽组生物标志物研究提供参考.     

官能化聚四氢呋喃-b-聚异丁烯-b-聚四氢呋喃三嵌段共聚物的合成与性能

采用2-氯-2,4,4-三甲基戊烷或对二枯基氯为引发剂和TiCl4或FeCl3为共引发剂,引发异丁烯(IB)可控/活性正离子聚合与官能端基转化,设计合成不同分子量及窄分子量分布的端基官能化聚异丁烯,如双端烯丙基溴官能化聚异丁烯(Br-PIB-Br)或双端烯丙基胺官能化聚异丁烯(H2N-PIB-NH2).采用烯丙基溴/高氯酸银体系引发四氢呋喃(THF)开环聚合,合成聚四氢呋喃活性链(PTHF+).进一步通过将IB可控/活性正离子聚合与THF可控/活性正离子开环聚合2种方法相结合,设计合成2种新型官能化聚四氢呋喃-b-聚异丁烯-b-聚四氢呋喃(PTHF-b-PIB-b-PTHF)三嵌段共聚物:(1)以上述Br-PIB-Br为大分子引发剂,在AgClO4作用下引发THF活性正离子开环聚合,采用水终止活性链端,设计合成双端为羟基的HO-PTHF-b-PIB-b-PTHF-OH三嵌段共聚物(简称:FIBF-OH);(2)以上述合成的PTHF+活性链与H2NPIB-NH2链端胺基发生高效亲核取代反应,设计合成中间链段连接点含―NH―官能基团的PTHF-b-HNPIB-NH-b-PTHF三嵌段共聚物(简称:FIBF-NH).在上述三嵌段共聚物中,极性PTHF链段与非极性PIB链段的热力学不相容,导致其呈现明显的微相分离,且微观形态与共聚组成相关.PTHF均聚物易结晶,在上述共聚物中由于PTHF链段单端受限致其结晶性减弱.三嵌段共聚物分子链的中间连接点含―NH―官能基团,具有更强的氢键作用,促进PTHF链段重排并结晶,易形成更紧密的超分子网络结构,导致即使在PTHF链段相对分子量为0.7 kg·mol^-1时仍具有较强的结晶性,且结晶熔融温度明显提高.此外,由于FIBF-NH中形成超分子网络结构,使材料具有优异的自修复性能,材料表面的切痕在常温下10 min后可以完全自愈合.本文设计合成的新型官能化PTHF-b-PIB-b-PTHF三嵌段共聚物兼具有PTHF与PIB的优良性能,在生物医用、智能修复等功能材料领域具有潜在的应用前景.     

由脂肪族二酰胺二醇合成聚酯酰胺及表征

利用脂肪族二元酸酯与乙醇胺反应容易获得的对称二酰胺二醇,经缩聚合成聚酯酰胺预聚体,并针对端羧基和端羟基同时扩链来提高分子量,获得可生物降解的聚酯酰胺.首先将N,N′-二(2-羟乙基)草酰胺(HEOA)或N,N′-二(2-羟乙基)己二酰胺(HEHA)与己二酸和丁二醇缩聚,制备同时带有端羧基及端羟基的脂肪族聚酯酰胺预聚体,通过1,4-双(2-噁唑啉)苯及己二酰双己内酰胺混合扩链剂扩链,获得高分子量脂肪族聚酯酰胺,并通过红外、1H-NMR、DSC及TGA对其结构和热性能进行了表征.结果表明,预聚体在制备过程发生了一定的酯-酰胺交换反应;扩链后聚合物的熔点、熔融焓和热稳定性有所下降;但热稳定性仍接近或略高于聚己二酸丁二酯.     

赖氨酸胍基化对蛋白质组分析的影响

赖氨酸胍基化在蛋白质组学定性和定量研究中起着重要作用,本文系统分析了胍基化前后,HeLa细胞蛋白质经胰蛋白酶酶解产生的3种不同类型肽段的质谱鉴定情况,并探讨了不同肽段质谱响应改变的内在原因。发现赖氨酸在侧链能选择性地发生胍基化反应（其选择性达到96.8%）,转化为高精氨酸,碱性增强。因此在正离子质谱模式下,C端为赖氨酸的肽段产生了更多的y离子,提供了许多新的离子碎片信息。在鉴定结果中,此类肽段所占总肽段的比例由原来的51.7%上升为57.3%,并且有1015条新的肽段被检测到。对于不含有赖氨酸的肽段,其鉴定结果在胍基化前后基本没有变化。结果表明,胍基化可以在一定程度上提高质谱鉴定的灵敏度和互补性,提高蛋白质分析的覆盖率。     

低能氮离子诱发丙酮与重水溶液的反应机理

利用氮气火花放电产生离子,其中的正离子在阴极位降的加速下“注入”到丙酮的重水溶液中,诱发其中的化学反应.利用气相色谱 质谱（GC MS）分析离子注入后的样品,证实有氘代产物（CH3COCH2D）、氘羟基取代产物（CH3COCH2OD）生成,这表明低能N＋诱发重水溶液中的反应主要是由于重水分子分解产生的自由基引起的,其中氘自由基和氘羟基自由基起重要作用;同时,产物中还检测到氘代乙酸（CH3COOD）和氘氨基丙酮（CH3COCH2ND2）,说明反应是在氧化性氛围中进行的,氮离子俘获重水中的氘形成氘氨基可能是氘氨基取代产物生成的主要原因,也是氮“沉积”在溶液中的重要形式.这些结果对初步揭示低能离子诱发水溶液的反应机理具有一定的意义.     

含不同侧氨基密度的PLGA-(ASP-Diol)x-PLGA共聚物的合成与表征

以N-(苄氧羰基)-L-天冬氨酸和亚硫酰氯反应制备了N-苄氧基天冬氨酸酐,将其与不同链长的二醇(乙二醇、二缩三乙二醇、聚乙二醇200和600)缩聚,合成了含端羟基的天冬氨酸-二醇交替预聚物(ASP-Di-ol)x;以其为大分子引发剂,辛酸亚锡为催化剂进行丙交酯/乙交酯(摩尔比75∶25)开环共聚,合成系列含侧氨基的天冬氨酸-二醇-聚乙丙交酯[PLGA-(ASP-Diol)x-PLGA]多元三嵌段共聚物.用FTIR,1HNMR,EA,DSC和GPC对共聚物结构进行表征.结果表明,影响预聚物分子量的主要因素不是二醇的分子量,而是其端羟基的活性.随着二醇链段长度增加,多元共聚物中氨基含量降低,玻璃化转变温度也明显下降.通过改变二醇链段的长度(或分子量)可有效地控制PLGA-(ASP-Diol)x-PLGA中侧氨基的密度及分布.     

聚乙二醇单甲醚-聚L-赖氨酸嵌段共聚物的合成及其表征

以L-赖氨酸为原料,先制备Nε-苄氧羰基-L-赖氨酸,光气法合成Nε-苄氧羰基-L-赖氨酸-N-羧酸酐[Lys-(Z)-NCA]。以聚乙二醇单甲醚(MPEG)为原料,制备了端氨基聚乙二醇单甲醚(MPEG-NH2),并以此为大分子引发剂,在氯仿中引发Lys-(Z)-NCA开环聚合,经无水溴化氢脱苄,合成不同组成和分子量的聚乙二醇单甲醚-聚L-赖氨酸嵌段共聚物。用IR1、H-NMR、GPC、DSC等对共聚物结构进行了表征。结果表明:MPEG-NH2引发Lys-(Z)-NCA开环聚合得到的是嵌段共聚物,通过1H-NMR谱计算得到了共聚物MPEG-PLL-1、MPEG-PLL-2、MPEG-PLL-3、MPEG-PLL-4中PLL链段的摩尔分数分别为0.553、0.795、0.848、0.861,共聚物数均分子量(Mn)分别为2.3×104、6.1×104、8.6×104、9.5×104。     

羧甲基壳聚糖衍生物及其振动光谱的理论研究

用量子化学从头算STO 3G法研究了羧甲基壳聚糖及其衍生物的结构和稳定性，计算结果表明:1)壳聚糖单体经羧甲基化后，得到2种可能的产物，其中羧甲基在壳聚糖单体2位氨基上的取代产物较6位羟基上的取代产物稳定； 2)以羧甲基壳聚糖为母体经加成反应，得到羧甲基壳聚糖衍生物（2 羟基 3 丁氧基）丙基 羧甲基壳聚糖的2个异构体， 其中构型1更稳定.在优化构型的基础上，计算所得的构型1的振动光谱与实验结果相吻合.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。