【作者】 罗红军；

【导师】 罗文鸿；

【作者基本信息】 汕头大学 ， 生化与分子生物学， 2006， 硕士

【摘要】 氨基脲敏感型胺氧化酶（Semicarbazide-sensitive amine oxidase，SSAO；EC1．4．3．6）是一类对氨基脲和其它肼类化合物敏感、含有铜离子和6-羟基多巴醌的胺氧化酶。SSAO可催化多种伯胺脱氨生成相应的醛、过氧化氢和氨（RCH₃NH₂+O₂+H₂O→RCHO+H₂O₂+NH₃）。甲胺是SSAO的生理底物之一，经SSAO催化脱氨生成甲醛、H₂O₂和氨。甲胺在尿液中大量存在，同时也分布在血液和组织中。甲胺可经体内代谢生成，或从食物、饮料及香烟烟雾中摄取。甲醛性质非常活泼，易与多种生物分子反应形成大分子加合物，可与蛋白质或单链DNA形成交联物。研究显示，内源性甲醛能增强蛋白糖基化，与体内蛋白质发生交联，从而可能造成血管内皮细胞的损伤，是引发动脉粥样硬化和糖尿病并发症如视网膜病变的潜在危险因素之一。此外，研究发现SSAO在葡萄糖摄取及抑制脂肪水解中起重要作用，而具有调节淋巴细胞黏附与迁移、与炎症相关的血管黏附蛋白-1（VAP-1）被发现与SSAO相同。SSAO催化的反应在这两个生理功能中起关键作用，采用小分子SSAO抑制剂可明显阻断其调控作用。因此，在第一部分的研究中，我们观察了3种常见的实验动物小鼠、大鼠和兔的血浆SSAO活性、甲胺和甲醛浓度，进而分析甲胺及其代谢产物甲醛在动物体内的药代动力学，为进行长期毒理实验打下基础，以进一步了解SSAO与内源性甲醛的病理生理学意义。在第二部分，我们采用SSAO高效抑制剂N′-（2-Phenylallyl） hydrazine hydrochloride （LJP1207）及SSAO首选底物苯甲胺，观察SSAO对细菌脂多糖（LPS）诱导急性炎症大鼠血浆一氧化氮（NO）和葡萄糖浓度的影响。更多还原

【Abstract】 Semicarbazide-sensitive amine oxidase （ EC 1.4.3.6; SSAO ） are an group of enzymes containing copper and 6-hydroxydopa quinone, sensitive to inhibition by semicarbazide and other hydrazine compounds. The enzyme can convert primary amines into the corresponding aldehydes, while generating hydrogen peroxide and ammonium at the same time RCH3NH2 + O₂ + H₂O → RCHO + H₂O₂ + NH₃. Methylamine （ MA ） is a endogenous substrate for SSAO and can be deaminated to formaldehyde （ FA）, hydrogen peroxide and ammonium. It is abundantly present in urine and also detected in blood and tissues. MA can be derived from several metabolic pathways and ingested from food, drinks and cigarette smoke. FA is extremely reactive and capable of inducing intra- and inter-moleculer cross-linkage between proteins and DNAs. It has been reported that FA produced endogenously via deamination of MA by SSAO. FA can enhance glycosylation of protein and cross-link with protein in vivo, cause endothelial injury and may be a potential risk factor for initiation of atherosclerosis and diabetic complication such as retinopathy. Recently, SSAO has been found to play an important role in glucose uptake and inhibition of lipolysis. And surprisingly, Vascular adhesion protein-1 （ VAP-1 ）, an endothelial molecular supporting the adhesence and transmigration of blood-borne lymphocytes to the vascular lining under shear and relating to inflammation, is identified same to SSAO. The enzymatic function of SSAO play a critical role in the physiological function described above and can be completely blocked by specific SSAO inhibitor. Therefore, in the first part of research, we investigated plasma SSAO activity, baseline MA and FA concentration and compared the pharmacokinetics of MA, and its metabolite FA in mice, rats and rabbits, So as to lay a fundation for long-lasting toxicity experiment test and further understand the physiological and pathological significance of plasma SSAO and endogenous FA. In the second part, nitric oxide （ NO ） and glucose concentrations in LPS-induced acute inflammatory rats were monitored in the presense of N’- （ 2-Phenylallyl ） hydrazine hydrochloride更多还原