Kaitaniemi Sam, Elovaara Heli, Grön Kirsi, Kidron Heidi, Liukkonen Janne, Salminen Tiina, Salmi Marko, Jalkanen Sirpa, Elima Kati
MediCity Research Laboratory, University of Turku, and National Institute for Health and Welfare, Tykistökatu 6, 20520 Turku, Finland.
Cell Mol Life Sci. 2009 Aug;66(16):2743-57. doi: 10.1007/s00018-009-0076-5. Epub 2009 Jul 9.
Semicarbazide-sensitive amine oxidases (SSAOs) catalyze oxidative deamination of primary amines, but the true physiological function of these enzymes is still poorly understood. Here, we have studied the functional and structural characteristics of a human cell-surface SSAO, AOC2, which is homologous to the better characterized family member, AOC3. The preferred in vitro substrates of AOC2 were found to be 2-phenylethylamine, tryptamine and p-tyramine instead of methylamine and benzylamine, the favored substrates of AOC3. Molecular modeling suggested structural differences between AOC2 and AOC3, which provide AOC2 with the capability to use the larger monoamines as substrates. Even though AOC2 mRNA was expressed in many tissues, the only tissues with detectable AOC2-like enzyme activity were found in the eye. Characterization of AOC2 will help in evaluating the contribution of this enzyme to the pathological processes attributed to the SSAO activity and in designing specific inhibitors for the individual members of the SSAO family.
氨基脲敏感胺氧化酶（SSAO）催化伯胺的氧化脱氨反应，但这些酶真正的生理功能仍知之甚少。在此，我们研究了人细胞表面SSAO——AOC2的功能和结构特征，它与特征更明确的家族成员AOC3同源。研究发现，AOC2在体外的首选底物是2-苯乙胺、色胺和对-酪胺，而非AOC3偏爱的底物甲胺和苄胺。分子模拟表明AOC2和AOC3之间存在结构差异，这使AOC2有能力将更大的单胺用作底物。尽管AOC2 mRNA在许多组织中都有表达，但仅在眼部组织中发现了具有可检测到的AOC2样酶活性。对AOC2的特性进行表征将有助于评估该酶对归因于SSAO活性的病理过程的作用，并有助于设计针对SSAO家族各成员的特异性抑制剂。
