一氧化氮,新发现的一种信使分子

１９９８年,诺贝尔生理和医学奖授予了３位美国药理学家弗奇戈特（ＲｏｂｅｒｔＦ．Ｆｕｒｃｈｇｏｔｔ）、伊格纳罗（ＬｏｕｉｓＪ．Ｉｇｎａｒｒｏ）和穆拉德（ＦｅｒｉｄＭｕｒａｄ）,因他们共同发现了一氧化氮是心血管系统中的信息分子。硝酸甘油作为一种心血管疾病药物,具有扩张血管活性的生理作用。在临床上应用已有１００多年历史,但其作用机理一直困扰着科学家们。从７０年代起,穆拉德教授及其合作者系统研究了硝酸甘油及其它具扩张血管活性的有机酸酯的药理作用。１９７７年,穆拉德发现硝酸甘油等有机酸酯必须代谢为一氧化氮…     

NO：一种重要的生物信使分子

一氧化氮（ｎｉｔｒｉｃｏｘｉｄｅ,ＮＯ）以其多样而新颖的生理,病理作用和广泛的组织分布,得到国内外学者的关注,研究表明,ＮＯ是一种重要的细胞内信使分子和神经递质,参与血管调节,炎症免疫反应等过程,Ｌ－Ａｒｇ－ＮＯ途径异常和ＮＯ产生异常,会引起某些疾病,从ＮＯ抑制剂和ＮＯ供体两方面,提出ＮＯ相关性疾病的治疗方法。     

兼具SOD和GPX活力的双功能酶的制备及性质研究

用苯甲基磺酰氟（ＰＭＳＦ）和Ｈ２Ｓｅ相继处理铜锌超氧化物歧化酶（Ｃｕ,Ｚｎ－ＳＯＤ）,将酶分子中的丝氨酸（Ｓｅｒ）转化为硒代半胱氨酸（ＳｅＣｙｓ）,从而引入了谷胱甘肽过氧化物酶（ＧＰＸ）的催化基因,使其在ＳＯＤ酶活性大部分保留的情况下,具有ＧＰＸ活性,其ＧＰＸ活力是ＰＺ５１活力的３０倍,研究了双功能酶的最佳制备条件,包括ＰＭＳＦ的剂量、反应最适温度及Ｈ２Ｓｅ处理时间等,并用电子能谱、ＤＴＮＢ等方法     

兼具SOD和GPX活力的双功能酶的制备及性质研究

用苯甲基磺酰氟（ＰＭＳＦ）和Ｈ_２Ｓｅ相继处理铜锌超氧化物岐化酶（Ｃｕ,Ｚｎ－ＳＯＤ）,将酶分子中的丝氨酸（Ｓｅｒ）转化为硒代半胱氨酸（ＳｅＣｙｓ）,从而引入了谷胱甘肽过氧化物酶（ＧＰＸ）的催化基团,使其在ＳＯＤ酶活性大部分保留的情况下,具有ＧＰＸ活性,其ＧＰＸ活力是ＰＺ５１活力的３０倍。研究了双功能酶的最佳制备条件,包括ＰＭＳＦ的剂量、反应最适温度及Ｈ_２Ｓｅ处理时间等,并用电子能谱、ＤＴＮＢ等方法测定了双功能酶的硒含量;测定了双功能酶对不同底物的米氏常数及双功能酶的荧光光谱、紫外吸收光谱及稳定性。     

NO对He-Ne激光和增强UV-B辐射小麦幼苗气孔运动的作用机理研究

为探讨NO对He-Ne激光和增强UV-B辐射小麦（Triticum aestivuml）气孔运动的作用机理,采用低剂量（5 mW.mm-2）He-Ne激光和增强（10.08 kJ.m-2.d-1）UV-B辐射并结合药理学实验和激光共聚焦显微技术,对ML7113小麦的叶片及表皮条进行不同的处理,结果显示：（1）UV-B辐射既可诱导小麦叶片气孔关闭,又能够明显增加气孔保卫细胞和叶片的NO水平,且NO清除剂明显抑制了UV-B辐射诱导的小麦叶片气孔关闭,同时气孔保卫细胞和叶片内的NO含量明显减少。（2）一氧化氮合酶（NOS）抑制剂L-NAME对经UV-B辐射诱导的小麦幼苗气孔开度及保卫细胞和叶片内NO含量的抑制程度明显大于硝酸还原酶（NR）抑制剂NaN3对其的抑制程度,说明一氧化氮合酶（NOS）合成途径是小麦叶片经UV-B辐射后NO的主要产生途径。（3）就气孔开度而言,L〉CK〉BL〉B。就小麦叶片及保卫细胞内NO含量而言,B〉BL〉CK〉L。就硝酸还原酶（NR）和一氧化氮合酶（NOS）的活性而言,B组NR活性最低,NOS活性最高,L组NR活性最高,NOS活性最低。表明经He-Ne激光和增强UV-B辐射诱导的小麦气孔开度的变化确实与保卫细胞及叶片中NO含量的多少有关,气孔开度的减小及增大对应于NO含量的增多或减少,同时进一步证实了小麦叶片经He-Ne激光单独辐照后,NO的主要合成途径也来源于NOS途径。     

一种兼具研究与应用开发价值的盐生植物——海马齿

海马齿(Sesuvium portulacastrum L.)是一种生长在热带和亚热带滨海地区的多年生兼性草本盐生植物。综述了海马齿在耐干旱、高盐及重金属离子机理等方面的研究进展,探讨了其潜在的开发价值及可能的用途。     

培养的大鼠海马神经元胞内Ca2＋和 NO 双标记方法研究

以培养 8 ～ 10 天的大鼠海马神经元为对象,选择 Calcium Orange AM 和 DAF-FM diacetate 为 Ca2＋和一氧化氮 (NO) 的荧光指示剂,建立了基于激光扫描共聚焦显微技术的细胞内 Ca2＋和 NO 双标记检测方法 . 此方法对 Ca2＋和 NO 进行分步染色,然后应用激光扫描共聚焦显微镜 (LSCM) 的双轨迹 (Two Track) 模式,通过快速切换激光实现对细胞内 Ca2＋和 NO 的同时检测 . 实验结果显示,两种染料之间无串扰现象;在 N- 甲基 -D- 天冬氨酸 (NMDA) 刺激下,海马神经元胞内 Ca2＋快速升高,随后达到平台期并有波动, NO 则稳定持续升高,这些变化过程与单标记的结果一致;双标记层切序列图像显示细胞内 Ca2＋和 NO 都较集中分布于细胞中部,但在细节上两者的分布存在差异 . 此双标记方法能同时检测培养的海马神经元胞内 Ca2＋和 NO ,为研究神经元胞内 Ca2＋和 NO 的相互调控作用提供了一种新的手段 .     

一种小白菜叶细胞溶质铜锌超氧化物歧化酶的纯化和性质研究

<正> 超氧化物歧化酶(SOD)是生物体内重要的金属酶。有关植物SOD同工酶的研究文献报道较多,但对酶的纯化及性质研究报道较少。本文简要报道一种小白菜叶细胞溶质Cu·Zn-SOD的纯化及其性质。 材料为小白菜(Brassica chinensis L.),品种上海青。酶活力测定用本室改良的邻苯三酚自氧化法。蛋白质测定按文献[2]进行。酶纯化方法参照文献[3]。酶活性染色参照文     

一种新型单链抗体血栓导向显像剂的制备和部分性质研究

 利用对血栓部位活化血小板α 颗粒膜蛋白GMP 140有亲和特异性的单克隆抗体SZ5 1的血栓部位导向作用 ,并利用金属硫蛋白的高金属结合能力 ,在基因工程水平构建分子量适中的单链抗体血栓导向显像剂 .1分子单抗SZ5 1单链抗体 (ScFv SZ5 1)与 1分子小鼠金属硫蛋白 (MT Ⅰ )cDNA的重组基因拼接产物 ,在大肠杆菌菌株BL2 1(DE3)pLysS中进行发酵表达 ,重组蛋白HLMT表达量为 4 0mg L发酵液 .该重组蛋白以包涵体形式存在于菌体中 .通过一种有效的包涵体制备方法可获得目的蛋白含量为 84 %的包涵体沉淀 .在优化的条件进行了包涵体的变复性 ,复性液先后经过Q SepharoseFF阴离子交换层析和SephadexG 5 0凝胶过滤层析进行纯化 .SDS PAGE鉴定了重组蛋白纯度达 95 %以上 .HPLC进一步证明了最终纯化产品的均一性 .质谱测定HLMT分子量为 384 31 3,与理论值基本相符 .等电聚焦电泳测定pI为 3 0 .Western印迹结果表明 ,HLMT中单链抗体部分具有与活化血小板α 颗粒膜蛋白GMP 140结合特异性 .原子吸收分光光度计法 (AAS)证明 ,HLMT中金属硫蛋白保持了原金属结合活性 .重组蛋白HLMT可以进一步进行核素标记实验和动物体内血栓显像实验     

在污染环境下带时滞和脉冲输入两种营养液和一种微生物模型性质的研究

提出并研究污染环境下带时滞和脉冲输入的恒化器模型,利用脉冲方程比较定理得到微生物灭绝周期解全局吸引和系统持续生存的充分条件,最后给出一个简单讨论.     

New potent inhibitors of angiotensin converting enzyme

Using an earlier model of the favoured orientation of binding functions of angiotensin converting enzyme (ACE) inhibitors, it has been possible to postulate a new, 7,6-bicyclic system, based on hexahydropyridazine, which might be expected to have high potency. Some members of this system which have been synthesised have been shown to be very active ACE inhibitors, in vitro and in vivo.     

Ketomethylureas. A new class of angiotensin converting enzyme inhibitors

The design rationale for a new series of tripeptide derived angiotensin converting enzyme (ACE) inhibitors, which we term "ketomethylureas", is described. Analogs of tripeptide substrates (i.e. N-benzoyl-Phe-Ala-Pro) in which the nitrogen atom of the scissile amide bond and the adjacent asymmetric carbon atom of the penultimate amino acid residue are formally transposed give rise to this novel class of inhibitors. The most potent ketomethylureas inhibit ACE with I50 values in the nM range.     

The history of inhibitors of angiotensin converting enzyme.

This review paper by Sir John Vane, The Nobel Prize Laureate for the first time reveals the insides of discovery of inhibitors of angiotensin converting enzyme (ACE-1), presently known as important drugs for the treatment of hypertension, congestive heart failure and coronary artery disease.     

Kinetics of slow, tight-binding inhibitors of angiotensin converting enzyme

Five phosphorus-containing inhibitors of angiotensin converting enzyme were found to exhibit slow, tight-binding kinetics by using furanacryloyl-L-phenylalanylglycylglycine as substrate at pH 7.50 and T = 25 degrees C. Two of the inhibitors, (O-ethylphospho)-Ala-Pro (2) and (O-isopropylphospho)-Ala-Pro (3), are found to follow at minimum a two-step mechanism of binding (mechanism B) to the enzyme. This mechanism consists of an initial fast formation of a weaker enzyme-inhibitor complex (Ki = 130 nM for 2 and 180 nM for 3) followed by a slow reversible isomerization to a tighter complex with measurable forward (K3) and reverse (k4) rate constants (k3 = 4.5 X 10(-2) s-1 for 2 and 5.4 X 10(-2) s-1 for 3; k4 = 9.2 X 10(-3) s-1 for 2 and 3.5 X 10(-3) s-1 for 3). For the remaining three inhibitors, phospho-Ala-Pro (1), (O-benzyl-phospho)-Ala-Pro (4), and (P-phenethylphosphono)-Ala-Pro (5), a one-step binding mechanism (mechanism A) is observed under the conditions of the experiment. The second-order rate constants k1 (M-1 s-1) for the binding of these inhibitors to converting enzyme are found to have values more than 3 orders of magnitude lower than the diffusion-controlled limit for a bimolecular reaction involving the enzyme, viz., 3.9 X 10(5) for 1, 2.2 X 10(5) for 4, and 4.8 X 10(5) for 5.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heart failure and first dose hypotension after angiotensin converting enzyme inhibitors

The first-dose induced decrease in blood pressure in some patients following the administration of ACE inhibitors is a fact causing some concern among clinicians prescribing these drugs. However, an overview of clinical trials and the authors' own experience clearly point to the possibility of reducing the incidence and/or severity of first-dose hypotension. Apart from appropriate clinical measures to be taken, the choice of the ACE inhibitor seems to be of crucial importance as some (fosinopril, perindopril) produce less hypotension than others. Thus, with due circumspection, ACE inhibitors can safely retain their position as the cornerstone of the treatment of chronic heart failure.     

Perindopril and ramipril phosphonate analogues as a new class of angiotensin converting enzyme inhibitors

A series of phosphonate analogues related to perindopril and ramipril were prepared and tested to estimate their ability to inhibit angiotensin converting enzyme. These new synthesized compounds were active ACE inhibitors with a promising activity.