Phospholipases A2

磷脂酶 A2
  • 文章类型: Journal Article
    自1956年以来,非洲蜜蜂已在美洲蔓延,因此导致人类和动物死亡,原因是与阿根廷接触美国有关的大规模袭击。在巴西,在过去5年中,登记的事故超过100,000起,共有303人死亡。为了治疗如此大规模的袭击,巴西研究人员开发了第一个针对非洲化蜜蜂刺痛暴露的特定抗蛇毒血清。这个独特的产品,世界上第一个这样的人,在2期临床试验中,已经对20名患者进行了安全测试。为了开发抗蛇毒血清,采用标准化方法从非洲蜜蜂中提取主要毒液抗原,以免疫产生血清的马。这个过程涉及提取,净化,分馏,表征,并使用质谱鉴定毒液(apitoxin),以使用主要毒素(蜂毒素及其亚型和磷脂酶A2)产生用于马超免疫的标准化抗原。当前指南描述了毒液抗原的整个生产链的标准化,符合监管机构要求的良好生产规范(GMP)。在此过程中,重点放在蜜蜂和马的福利上,以及开发新的生物制药以最终挽救生命。
    Africanized bees have spread across the Americas since 1956 and consequently resulted in human and animal deaths attributed to massive attacks related to exposure from Argentina to the USA. In Brazil, more than 100,000 accidents were registered in the last 5 years with a total of 303 deaths. To treat such massive attacks, Brazilian researchers developed the first specific antivenom against Africanized honey bee sting exposure. This unique product, the first of its kind in the world, has been safely tested in 20 patients during a Phase 2 clinical trial. To develop the antivenom, a standardized process was undertaken to extract primary venom antigens from the Africanized bees for immunization of serum-producing horses. This process involved extracting, purifying, fractionating, characterizing, and identifying the venom (apitoxin) employing mass spectrometry to generate standardized antigen for hyperimmunization of horses using the major toxins (melittin and its isoforms and phospholipase A2). The current guide describes standardization of the entire production chain of venom antigens in compliance with good manufacturing practices (GMP) required by regulatory agencies. Emphasis is placed upon the welfare of bees and horses during this process, as well as the development of a new biopharmaceutical to ultimately save lives.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Comparative Study
    A model structure of Naja naja kaouthia cobra venom phospholipase A2 has been constructed by utilizing molecular modeling techniques. Analysis of the model and available biochemical data reveal the presence in this enzyme of a putative recognition site for choline derivatives in loop 57-70 made up of residues Trp-61, Tyr-63, Phe-64, and Lys-65, together with Glu-55. The magnitude and shape of the electrostatic potential in this binding site are approximately 80% similar to that in the McPC603 antibody binding site specifically recognizing phosphocholine. Docking studies indicate that the recognition site we now describe and the phosphocholine head of an n-alkylphosphocholine molecule are complementary both sterically and electronically, mainly due to anion-cation and cation-pi interactions. Moreover, binding enthalpies of n-heptylphosphocholine to this site are found to parallel the catalytic rate of pancreatic, mutant pancreatic, and cobra venom phospholipase A2 enzymes acting on dihexanoylphosphatidylcholine micelles, suggesting that it behaves as an activator site. This proposal is in keeping with the \"dual phospholipid\" model put forward to account for the phenomenon of interfacial activation. This novel site is also shown to be able to discriminate choline derivatives from ethanolamine derivatives, in accord with experimental data. On the basis of the results obtained, two functions are assigned to this putative activator site: (i) desolvation of the lipid-enzyme interface, particularly the surroundings of tyrosine at position 69 (Tyr-63), and (ii) opening of the entrance to the active site by means of a conformational change of Tyr-63 whose chi 2 angle rotates nearly 60 degrees.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

公众号