Novel Therapeutic Approaches for Narcotic Overdose

麻醉药物过量的新治疗方法

• 批准号: 7479832
• 负责人: PHILIP M POTTER
• 金额: $ 27.39万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-30 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7479832
• 关键词: 6-O-monoacetylmorphine; Accident and Emergency department; Acids; Active Sites; Acute; Alcohols; Amino Acid Sequence; Amino Acids; Animal Model; Animals; Area; Arrhythmia; Biochemical; Blood; Carboxylic Ester Hydrolases; Cocaine; Cocaine Abuse; Complex; Development; Engineering; Enzymes; Esters; Ethanol; Exposure to; Goals; Heroin; Hospitals; Human; Human Activities; Hydrolase; Hydrolysis; Injection of therapeutic agent; Liver; Measures; Metabolism; Methods; Morphine; Mus; Mutation; Naloxone; Narcotics; Numbers; Overdose; Patients; Pharmaceutical Preparations; Plasma; Principal Investigator; Proteins; Reaction; Reporting; Seizures; Site; Stream; Structure; Symptoms; Testing; United States; analog; base; carboxylesterase; cocaethylene; design; ecgonine; esterase; homatropine; human carboxylesterase 1; improved; methyl group; mutant; novel; novel therapeutics; programs; purge; urinary

DESCRIPTION (provided by applicant): Cocaine and heroin are metabolized by carboxylesterases (CE) present in the liver. With cocaine, the methyl group is removed by human carboxylesterase 1 (hCE1) to produce benzyl ecgonine, the major inactive metabolite of the drug. With heroin, both methyl esters are sequentially hydrolyzed by the same enzyme to yield 6-monoacetylmorphine and subsequently, morphine. We have recently determined the x-ray crystal structure of hCE1, in complex with the cocaine and heroin analogs, homatropine and naloxone, respectively. Using this information, we will engineer mutations within the hCE1 amino acid sequence to improve its ability to hydrolyze cocaine. These enzymes will be tested in an esterase-deficient animal model to determine whether they can be used to purge cocaine from the blood stream. Additionally, we will determine the ability of these mutants to transesterifiy cocaine in the presence of ethanol to form cocaethylene, and measure the hydrolysis of this compound by different hCE1 proteins. The Specific Aims of this application are therefore to: 1) generate hCE1 mutants with improved catalytic efficiency for cocaine hydrolysis; 2) determine the amino acid residues involved in the transesterification reaction of cocaine to cocaethylene by hCE1; 3) elucidate crystal structures of engineered forms of hCE1 in complexes with cocaine and cocaine analogues; and 4) assess the impact of mutant forms of hCE1 on plasma esterase-deficient mice exposed to cocaine. Overall, these studies should allow development of novel therapeutic approaches for the treatment of cocaine overdose.

描述（由申请人提供）：可卡因和海洛因通过肝脏中存在的羧酸酯酶（CE）代谢。对于可卡因，人羧酸酯酶 1 (hCE1) 会去除甲基，产生苄基芽子碱，这是该药物的主要非活性代谢物。对于海洛因，两种甲酯依次被同一酶水解，产生 6-单乙酰吗啡，随后产生吗啡。我们最近确定了 hCE1 的 X 射线晶体结构，分别与可卡因和海洛因类似物、后马托品和纳洛酮形成复合物。利用这些信息，我们将设计 hCE1 氨基酸序列内的突变，以提高其水解可卡因的能力。这些酶将在酯酶缺陷的动物模型中进行测试，以确定它们是否可以用于清除血液中的可卡因。此外，我们将确定这些突变体在乙醇存在下将可卡因酯交换形成可卡乙烯的能力，并测量不同 hCE1 蛋白对该化合物的水解作用。 因此，本申请的具体目标是： 1) 生成具有改进的可卡因水解催化效率的 hCE1 突变体； 2)通过hCE1确定参与可卡因转酯化反应的氨基酸残基； 3) 阐明可卡因和可卡因类似物复合物中 hCE1 工程形式的晶体结构； 4) 评估 hCE1 突变体对暴露于可卡因的血浆酯酶缺陷小鼠的影响。总的来说，这些研究应该能够开发出治疗可卡因过量的新治疗方法。