Extending fluorinase [C-18F]-bond biocatalysis for Positron Emission Tomography (PET)

扩展用于正电子发射断层扫描 (PET) 的氟酶 [C-18F] 键生物催化

• 批准号: EP/I034734/1
• 负责人: David O'Hagan
• 金额: $ 40.77万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FI034734%2F1
• 关键词: Extending; fluorinase; 18F; bond; biocatalysis

Positron emission tomography (PET) is the most sensitive functional imaging method clinically and it application is growing rapidly through the Western world and developing countries, particularly as a diagnostic imaging tool for cancers and degenerative neurological disorders. Many major hospitals and clinical research centres in the Europe, the US and Asia are now commissioning cyclotrons and developing PET research facilities locally. Fluorine-18 is an important isotope for PET. It has a relatively long half-life (109 mins) and is readily generated in a cyclotron in the form of [18F]-fluoride ion, in very high specificic activity (GBq's) from oxygen-18 water. As a consequence new methods to develop C-[18F]F bond formation for PET labelling are in demand, In general the link between fluorine chemistry and pharmaceutical/medical applications is strong. Approximately 20% of all pharmaceutical, since the 1950s, contain a fluorine atom and the bio-distribution of all new pharmaceutical products are required to be explored by PET, as part of clinical trials. Also new PET tracers are in demand as tools for early diagnosis as indicators of disease states. New fluorine chemistry is required to meet the demands of a growing and dynamic PET research community both in the UK and internationally. This proposal aims to develop a novel methodology for incorporating fluoride-18 into relevant orgaganic molecules.In this proposal we aim to exploit a novel enzyme which can form C-F bonds from fluoride ion. The fluorinase enzyme was discovered in 2002 (Nature, 2002, 416, 279) in St Andrews and it has been over-expressed and its structure (X-ray) and mechanism elucidated. The enzyme catalyses the reaction of fluoride ion and S-adenosyl-L-methionine (SAM) to generate 5'-FDA and L-methionine. It has proven to be a chemoselective biotransformation method for generating C-18F bonds from inorganic [18F]-fluoride. The fluorinase is the only example of an enzyme used in PET synthesis and in this regard it offers an entirely new method for incorporating fluorine. In practical terms it has emerged to be particularly appropriate, because PET uses picomolar [18F]-fluoride ion, but the over-expressed fluorinase enzyme is present at mg/ml (microM), and therefore the kinetics favour C-18F synthesis due to a large molar excess of enzyme. This is a research collaboration between the Universities of St Andrews and Aberdeen where the methods will be developed in St Andrews and the radiolabeling protocols carried out at the Aberdeen PET Centre, situated in the Royal Infirmary Hospital. The major focus of the research will concentrate on developing fluorinase based chemistry to prepare novel fluorine-18 small molecules that can be used to attach to proteins through site specific cysteine residues. It is a current objective to find novel methods to radiolabel proteins such as enzymes and antibodies, to monitor their in vivo distribution by imaging. A key strategy will explore substrate analogues for the fluorinase, which carry acetylene residues, such that a 'click' chemistry approach can be adopted.A secondary objective of the research is to exploit an efficient chemo-enzymatic synthesis of [18F]-fluoroacetyl-CoA, developed between St Andrews and Aberdeen, to prepare [18F]-fluorocitrate, [18F]-fluoromalate and [18F]-N-aceylglutamate, as novelties for in vivo imaging. In overview the research will present a range of new methodologies for PET chemistry for the incorporation of the fluorine-18 isotope into molecules of biological relevance. The research in generic and aims to expemplify new methods, for much wider applications by the growing international research community of PET radiochemists.

正电子发射断层扫描（PET）是临床上最灵敏的功能成像方法，在西方世界和发展中国家的应用正在迅速增长，特别是作为癌症和退行性神经系统疾病的诊断成像工具。欧洲、美国和亚洲的许多大型医院和临床研究中心现在都在当地调试回旋加速器并开发PET研究设施。氟-18是PET的重要同位素。它的半衰期相对较长（109分钟），很容易在回旋加速器中以[18F]-氟离子的形式从氧-18水中以非常高的比活度（GBq's）生成。因此，需要开发用于PET标记的C-[18F]F键形成的新方法。总的来说，氟化学与制药/医疗应用之间的联系很强。自20世纪50年代以来，大约20%的药品含有氟原子，所有新药品的生物分布都需要通过PET来探索，作为临床试验的一部分。此外，新的PET示踪剂作为疾病状态指标的早期诊断工具也是有需求的。新的氟化学需要满足不断增长的需求和动态PET研究社区无论是在英国和国际。本提案旨在开发一种将氟-18纳入相关有机分子的新方法。在这个建议中，我们的目标是开发一种新的酶，可以从氟离子形成C-F键。氟酶于2002年在圣安德鲁斯被发现（Nature, 2002, 416,279），并被过度表达，其结构（x射线）和机制被阐明。该酶催化氟离子与s -腺苷- l-蛋氨酸（SAM）反应生成5′-FDA和l-蛋氨酸。它已被证明是一种由无机[18F]氟生成C-18F键的化学选择性生物转化方法。氟酶是用于PET合成的酶的唯一例子，在这方面，它提供了一种全新的结合氟的方法。在实际应用中，由于PET使用的是皮摩尔[18F]氟离子，但过表达的氟酶以mg/ml（微米）存在，因此由于酶的大量摩尔过剩，动力学有利于C-18F的合成。这是圣安德鲁斯大学和阿伯丁大学之间的一项研究合作，这些方法将在圣安德鲁斯开发，而放射性标签协议将在位于皇家医院的阿伯丁PET中心进行。该研究的主要重点将集中在开发基于氟酶的化学方法，以制备新型的氟-18小分子，可用于通过特定位点的半胱氨酸残基附着在蛋白质上。目前的目标是寻找新的方法来放射性标记蛋白质，如酶和抗体，并通过成像来监测它们在体内的分布。一个关键的策略是探索氟酶的底物类似物，它携带乙炔残基，这样就可以采用“点击”化学方法。该研究的第二个目标是利用圣安德鲁斯和阿伯丁之间开发的[18F]-氟乙酰辅酶A的有效化学酶合成，制备[18F]-氟柠檬酸盐，[18F]-氟苹果酸盐和[18F]- n -乙酰谷氨酸盐，作为体内成像的新产品。总的来说，这项研究将提出一系列新的PET化学方法，以便将氟-18同位素纳入具有生物学意义的分子中。这项研究是通用的，旨在为不断增长的PET放射化学家国际研究界提供更广泛的应用的新方法。

项目成果

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Enzymatic Fluorination of Biotin and Tetrazine Conjugates for Pretargeting Approaches to Positron Emission Tomography Imaging.

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• DOI: 10.1002/cbic.201800234
• 发表时间: 2018
• 期刊: a European journal of chemical biology
• 作者: Lowe PT

Identification of a fluorometabolite from Streptomyces sp. MA37: (2R3S4S)-5-fluoro-2,3,4-trihydroxypentanoic acid.

• DOI: 10.1039/c4sc03540b
• 发表时间: 2015-02-01
• 期刊: Chemical science
• 影响因子: 8.4
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• 通讯作者: O'Hagan D