激肽释放酶的研究进展

激肽释放酶是一类丝氨酸蛋白酶，具有广泛的生物学功能和特殊的结构，由多基因家族构成，分布于各种动物体内，在大鼠和小鼠中尤为普遍。近年来，已发现人激肽释放酶基因家族含有15个成员，且都纵向排列位于19q13．4染色体上。本文综述了激肽释放酶在各种动物中的基因结构特点、表达调控等。同时，激肽释放酶参与多种生理和病理反应，尤其是在中枢神经系统疾病和癌症中，激肽释放酶都起着重要作用。     

人组织激肽释放酶与癌症

激肽释放酶 (kallikreins ,KLK)是一个具有高保守序列的、编码丝氨酸蛋白酶的多基因家族 ,存在于不同组织和生物液体中 ,可分为血浆激肽释放酶和组织激肽释放酶两大类。血浆激肽释放酶又称为Fletcher因子 ,正式命名后缩写为KLKB1。由位于4q35染色体上的单基因编码 ,与组织激肽释放酶分属不同基因家族。KLKB1由15个外显子组成 ,仅编码一个酶 ,该酶可使由肝脏产生的高分子前体物质激肽原 (kininogen)释放活性肽 -缓激肽 (bradykinin)。血浆激肽释放酶由肝细胞特异性表达。其功能是在血管紧张度调节和炎症反应过程中通过释放缓激肽参加血…     

激肽释放酶的快速分离纯化新工艺

目的 为了简化激肽释放酶的制备过程,提高激肽释放酶的纯度、收率和稳定性,建立了一种新的分离纯化工艺.方法 直接将胰酶溶解后上DEAE-琼脂糖快胶新型阴离子交换柱吸附,两步洗脱后目标蛋白加入保护剂PEG,经过丙酮低温沉淀,室温干燥即可得到激肽释放酶精品.结果 比活力大于550 U·mg-1,收率达73.6%,重复性较好.结论 所用工艺可快速分离纯化激肽释放酶.     

胰酶中激肽释放酶的含量测定

<正> 激肽释放酶[Kallikrein,EC 3,4,421」是一种糖蛋白,广泛存在于哺乳动物,包括人的胰脏、领下腺、尿中。激肽释放酶可作用于激肽原释出胰激肽,具有降低血压,促进子宫和肠活动的功能。适用于初老期循环障碍、高血压、脑动脉硬化等症;对血液循环障碍引起的组织营养不良、血管痉挛、四肢麻木,雷诺氏病也有治疗作用。在五十年代,日本从德国引入这一品种,据报导1980年日本有29个厂生产胰激肽释放酶共10亿片,销售额270亿日元,居动物生化药首位。近几年来,日本一些厂商竞相从我国进口胰酶生产胰激肽释放酶,其质量规格原以酪蛋白转化力作为标准,因此,     

纯化激肽释放酶(Purifying Kallidinogenase)英国专利1522359(1978)

<正> 本文谈的是纯化激肽释放酶Kallidinogenase(EC 3.4.4.21,商品名称Kallikrein)的一种改进方法,该酶由哺乳动物的胰脏提取。众所周知,有各种方法从“哺乳动物的胰脏”提取激肽释放酶(一种循环系统的激素),例如哺乳动物的胰脏本身、胰脏粉、或含有激肽释放酶的胰脏提取液,并纯化已提取了的粗激肽释放酶。关于得自哺乳动物胰脏的含激肽释放酶水提取液的纯化已经作出了各种建议。例如,一种已知类型的纯化方法,是使用多糖型非树脂物料,其中包括一种方法是使这种粗的激肽释     

激肽释放酶的精制方法

<正> 要求专利的范围是以下述情况为特点的激肽释放酶精制方法:将胰脏性激肽释放酶水溶液,调整到激肽释放酶等电点附近的pH4.0～5.0,最好是在pH4.5,然后与以伯胺、仲胺或叔胺为交换基的大孔型弱碱性阴离子交换树脂接触,在使激肽释放酶吸附到该树脂上以后,用含有0.5M以上盐浓度的电解质溶液从该吸附体上洗脱激肽释放酶。发明的详细说明本发明是关于激肽释放酶的精制方法。更详细地说,是采用以伯胺、仲胺或叔胺为交换基的弱碱性阴离子交换树脂,将由哺乳动物胰     

胰激肽释放酶国外临床概况

<正> 激肽释放酶(又称血管舒缓素),在国内颌下腺激肽释放酶早已有商品上市,但对其临床作用研究甚少。以前我们曾对激肽释放酶的国内外研究情况作过概述。本文就国外对胰激肽释放酶(简称胰K)的临床研究情况作一简介。激肽释放酶是一种蛋白水解酶,广泛存在于哺乳类动物的组织中,其中胰腺含量最高。在体内它作用于激肽原而释放出激肽,激肽能扩张血管、毛细血管、血管平滑肌,改善血液循环,起调节血压等作用,但对心脏活动没有影响。它也是一种活化因子,能使纤溶酶原激活成为纤溶酶,纤溶酶能把不溶性的纤维蛋白水解成可溶性小肽,从而导致血栓溶解,但作用比尿激酶缓慢。     

二、胰激肽释放酶对体外培养心肌细胞的影响

<正> 前已报导,小量胰激肽释放酶对麻醉犬心功能有正性肌力作用,剂量加大,对心脏有负性肌力作用,血压下降,心率减慢,TT1减小。又根据文献报导,胰激肽释放酶有促进男性生殖细胞增生和修复的功能,可能与DNA合成有关。为此,本实验室进一步探讨胰激肽释放酶对离体培养心肌细胞的搏动功能、DNA合成以及对缺氧缺糖是否有影响,现将实验结果报导于下: 方法与结果一、胰激肽释放酶对培养心肌细胞搏动功能的观察实验取用培养2～3天的大白鼠乳鼠(Wist-ar)心肌细胞,在倒置显微镜下选择一个搏动规律的细胞簇作为固定观察对象,记录正常搏动后,用Eagle培养基配制的胰激肽释放酶(20μl/ml)放入培养瓶内,记录给药1′、2′、5′、10′、15′、20′、30′心肌细胞的频率、节律、     

肾脏的降压系统与高血压

以肾脏分泌的激肽释放酶为中心构成激肽释放酶—激肽(Kallikrein—Kinin、简称K—K)系统;又以肾脏分泌的前列腺素为中心构成前列腺素(Prostaglandin,     

血管舒缓素的生产工艺和临床应用

<正> 激肽释放酶(Kallikreins,EC 3.4.21.8即旧分类法EC 3.4.4.21,我国药用商品名“血管舒缓素”)是一组具有特异性、局限性蛋白水解作用的丝氨酸蛋白酶。它们能使底物-激肽原(Kininogen)释放出一种多肽-激肽(Ki-nin),故此酶也称激肽原酶(Kininogenases)。它们通过释放具有药理活性的激肽对体内的血管和平滑肌有明显的作用。激肽是在结构上相似,能引起体内血压降低的一类多肽激素,它们主要是由不同专一性的激肽释放酶作用于激肽原所产生,其中以九肽的舒缓激肽     

Structural aspects of carbohydrates and the relation with their biological properties

Structural diversity of carbohydrates plays a crucial role in their large variety of roles in biological systems. This paper focuses on aspects of structure and biological functions of three classes of carbohydrates, N-linked oligosaccharides, blood group oligosaccharides and glycosaminoglycans. Conformations and dynamics in solution, as well as structure of protein-carbohydrate complexes are discussed. A short overview also describes theoretical and experimental methodologies that are used in current glycobiological research, particularly high-resolution NMR spectroscopy, X-ray crystallography and methods of computational chemistry.     

细菌脂蛋白生物合成调控研究进展

细菌脂蛋白是一组具有多种功能的膜蛋白。由于其广泛的功能，这些蛋白质对细菌的正常生长、分化和发育是必须的。脂蛋白的经典生物合成路径需要细胞质膜的3种酶：前脂蛋白二酰甘油基转移酶(Lgt)，脂蛋白信号肽酶Ⅱ(LspA)和脂蛋白N-酰基转移酶(Lnt)相继发挥催化作用，产生成熟的三酰化脂蛋白。这3种酶的缺失会导致革兰阴性菌的死亡及革兰阳性菌活力和致病能力的下降，并且这3种酶是原核生物所特有的，在人体中无同源类似物。因此这些酶是下一代广谱抗生素研发的潜在靶标。近几年来，这些酶的晶体结构已被相继解析出来，从而可以开展基于结构的药物设计。本文主要综述细菌脂蛋白生物合成路径以所涉及到的3种酶的晶体结构和生物学功能。     

鞘磷脂合酶的生物学功能及与动脉粥样硬化的关系

鞘磷脂是细胞膜及血浆脂蛋白中的重要脂质,有着广泛而重要的生物学功能,并与动脉粥样硬化的发生发展密切相关,其含量改变已成为动脉粥样硬化的独立危险因素之一;而鞘磷脂合酶是鞘磷脂合成的关键酶,其表达水平及活性高低直接影响到动脉粥样硬化的病理过程,有可能成为动脉粥样硬化治疗的新靶点。该文就鞘磷脂合酶的结构、生物学功能、在动脉粥样硬化形成过程中的作用,及其作为AS治疗潜在靶点的研究近况进行了全面的综述。     

含硫多肽类抗生素那西肽的研究进展

那西肽（nosiheptide）是一类由活跃链霉菌（Streptomyces actuosus）产生的新型环保含硫多肽类抗生素。本文就其结构与理化特性,生物学功能及作用机制,生产,提取工艺,测定方法,安全性及应用等方面进行了综述,对产那西肽的结构基因,菌种改良方面的研究进行了总结,对那西肽后续的研究进行了展望。     

Alpha-helical structure in the C-terminus of vasoactive intestinal peptide: functional and structural consequences

The conformational properties of vasoactive intestinal peptide (VIP) include the N-terminal randomized structure and the C-terminal long alpha-helical structure. We have previously observed that the N-terminal random coil structure plays a crucial role in the receptor-selectivity. Here, to clarify how the formation of the alpha-helix plays a role in its biological functions, we chemically synthesized VIP analogues modified at the C-terminus, mid-chain, and N-terminus of the alpha-helical region, and evaluated the relationship between their alpha-helical contents and their biological activities including relaxant effects on murine stomach and receptor-binding activities. VIP and VIP-(1-27) showed equipotent biological activities with 48% and 50% alpha-helical content, respectively, each of which corresponds to 14 amino acid residues. VIP-(1-26) was 10% and threefold less potent in relaxant and binding activities, respectively, compared with VIP, and its 49% alpha-helical content resulted in 13 residues involved in the alpha-helix. Further truncation from 25 to 21 resulted in decrease in the alpha-helical content from 43% to 29%, corresponding residues from 11 to 6, the relaxant activity from 72% to 4%, and the affinity to the membrane from 60-fold to over 10(4)-fold less potency. In addition, disruption of the mid-chain and the N-terminus in the alpha-helical stretch by oxidation of Met(17) and deletion of Thr(11) also inhibited biological activities. These findings suggest that the presence of alpha-helical structure forming in 14 amino acid residues between position 10 and 23 in VIP is essential to its biological functions and the C-terminal amino acid residues between position 24 and 27 are requisite for this alpha-helical formation.     

CYP4X1的结构、分布、表达调控及功能的研究进展

CYP4X1是CYP4新的亚家族成员,也是重要的Orphans CYPs成员之一。其核苷酸序列同源性分析显示CYP4X1结构在跨物种间是高度保守的,这预示着它具有重要的生物学功能。CYP4X1广泛存在于人体各组织中,尤其选择性在脑内高表达,提示其可能在神经血管功能中扮演关键作用。CYP4X1的表达存在昼夜节律调节、明显的性别差异和年龄差异以及外源物可诱导其表达。CYP4X1重要的生物学功能之一是代谢内源性大麻素Anandamide生成唯一的单加成产物14,15-EET-EA以及参与脂肪的代谢。EET-EAs可能发挥着EETs相似的生物学功能。此外,CYP4X1与肿瘤的分级有关,其可能成为肿瘤治疗的潜在药物靶标。     

Structural and functional studies of galectin-1: a novel axonal regeneration-promoting activity for oxidized galectin-1

Recently, we discovered oxidized galectin-1 as a factor that regulates initial axonal growth in the peripheral nerve after axotomy. Galectin-1 is a member of the galectins, a family of animal lectins ranging from Caenorhabditis elegans to humans, which is defined by their affinity for beta-galactosides and by significant sequence similarity in the carbohydrate-binding site. Galectin-1 is a homodimer with a subunit molecular mass of 14.5 kDa, which contains six cysteine residues per subunit. The cysteine residues should be in a free state in order to maintain a molecular structure that is capable of showing lectin activity. However, our structural analysis revealed that the axonal regeneration-promoting factor exists as an oxidized form of galectin-1, containing three intramolecular disulfide bonds. The oxidized galectin-1 exhibited marked peripheral nerve regeneration-promoting activity, although it showed no lectin activity. It was also revealed that oxidized galectin-1 exists as a monomer in a physiological solution. Galectin-1 seems to have a variety of biological functions. These functions could vary according to the time at which a biological function is taking place, as well as the site in which a biological function is taking place. In addition, these functions could vary according to the structure of galectin-1 by which a particular biological function is taking place. Disulfide bond formation alters the structure of galectin-1, so as to confer the novel ability to promote axonal regeneration. Oxidized galectin-1 likely acts as an autocrine or paracrine factor to promote axonal regeneration, functioning more like a cytokine than as a lectin.     

International Union of Pharmacology. LXVI. Orphan nuclear receptors

Half of the members of the nuclear receptors superfamily are so-called "orphan" receptors because the identity of their ligand, if any, is unknown. Because of their important biological roles, the study of orphan receptors has attracted much attention recently and has resulted in rapid advances that have helped in the discovery of novel signaling pathways. In this review we present the main features of orphan receptors, discuss the structure of their ligand-binding domains and their biological functions. The paradoxical existence of a pharmacology of orphan receptors, a rapidly growing and innovative field, is highlighted.     

Advances in chondroitin sulfate analysis: application in physiological and pathological States of connective tissue and during pharmacological treatment of osteoarthritis

Recent glycobiology studies have suggested fundamental biological functions for chondroitin sulfate (CS) and dermatan sulfate (DS), which are widely distributed as glycosaminoglycans (GAGs) sidechains of proteoglycans (PGs) in the extracellular matrix and at cellular level. Several biological functions are closely associated with the structure and in particular with the sulfation patterns of these polysaccharides. CS is also used as a structure-modifying osteoarthritis (OA) drug that reverses, retards, or stabilizes the pathology of OA, thereby providing symptomatic relief in the long-term treatment. Advances in analytical separational techniques, including agarose-gel electrophoresis, high-performance liquid chromatography (HPLC), capillary electrophoresis (HPCE), fluorophore-assisted carbohydrate electrophoresis (FACE) and electrospray ionization mass (ESI-MS) enable us to examine alterations of CS/DS with respect to their quantities and fine structural features in various pathological conditions, thus becoming applicable for diagnosis. Furthermore, sensitive analytical procedures enable us to follow the pharmacological application of CS in the treatment of OA and to monitor the progression of the disorder. In this review, the chromatographic and electromigration procedures developed to analyse and characterise CS/DS are presented. Moreover, a critical evaluation of the biological relevance of the results obtained by the developed methodology is discussed.     

海洋鞘类脂糖苷的研究进展

海洋鞘类脂糖苷化合物主要来自海绵，海星类海洋生物，总结近20年来海洋生物中鞘类脂糖苷（Glycosphingolipies,GSLs)化合物的研究进展，阐明鞘类脂糖苷化合物化学结构与生物活性的关系。