Masini-Repiso A M, Cabanillas A M, Andrada M C, Coleoni A H
Horm Metab Res. 1986 Nov;18(11):750-3. doi: 10.1055/s-2007-1012426.
Two functional forms of monoamine oxidase (MAO) defined as MAO A and MAO B have been described in several tissues. In this study the characteristics of MAO present in a particulate subcellular fraction of bovine thyroid tissue were investigated. The selective inhibitors of MAO, clorgyline (A form) and deprenyl (B form) were used. The monoamines 5-hydroxytryptamine (5-HT) (preferred of the A form), tyramine (both forms) and beta-phenylethylamine (PEA) (B Form) were used as substrates. MAO activity towards 5-HT was markedly inhibited by clorgyline. Tyramine oxidation was very sensitive to clorgyline and the curve obtained was in accordance with the presence of a high proportion of the A form. MAO activity towards PEA was also markedly inhibited by clorgyline. Deprenyl was not able to induce modifications in the MAO activity except when it was used at very high concentrations. According to these results the bovine thyroid tissue contains predominantly the A form of MAO. In this tissue PEA was deaminated by the A form of the enzyme.
单胺氧化酶（MAO）有两种功能形式，即MAO A和MAO B，已在多种组织中被描述。在本研究中，对牛甲状腺组织颗粒亚细胞组分中存在的MAO特性进行了研究。使用了MAO的选择性抑制剂氯吉兰（A形式）和司来吉兰（B形式）。单胺5-羟色胺（5-HT）（A形式优先作用底物）、酪胺（两种形式均可作用）和β-苯乙胺（PEA）（B形式作用底物）被用作底物。氯吉兰显著抑制MAO对5-HT的活性。酪胺氧化对氯吉兰非常敏感，得到的曲线表明存在高比例的A形式。氯吉兰也显著抑制MAO对PEA的活性。司来吉兰除非在非常高的浓度下使用，否则不能引起MAO活性的改变。根据这些结果，牛甲状腺组织主要含有MAO的A形式。在该组织中，PEA被该酶的A形式脱氨基。
