An unexpected side reaction in the guaiacol assay for peroxidase.
An unexpected side reaction in the guaiacol assay for peroxidase.
复制标题
过氧化物酶愈创木酚测定中出现意外的副反应。
DOI：
10.1016/0003-2697(92)90434-9
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发表时间：
1992
影响因子：
2.9
通讯作者：
GuziecJr,FS
中科院分区：
文献类型：
--
作者：
Taurog,A;Dorris,ML;GuziecJr,FS
在甲状腺过氧化物酶和乳过氧化物酶的常规愈创木酚测定中，使用新购自Aldrich Chemical Co.的愈创木酚瓶，我们惊奇地发现形成了蓝色而不是通常与该测定相关的预期琥珀色。这也观察到辣根，髓，和细胞色素c过氧化物酶。蓝色（Amax = 650 nm）不是用从其他两家化学公司获得的愈创木酚试剂形成的，也不是用在实验室中使用了10多年的旧Aldrich愈创木酚瓶形成的。在本研究中，我们提供的证据表明，形成的蓝色是密切相关的存在下，低浓度的邻苯二酚（约0.5摩尔%）的新奥德里奇愈创木酚试剂。邻苯二酚本身，即使在高得多的浓度下，也是过氧化物酶的非常弱的供体，形成浅粉红色。在Aldrich新愈创木酚中不形成蓝色，排除470 nm吸收产物。然而，后者的形成被抑制，并且使用Aldrich新愈创木酚进行测定导致过氧化物酶活性的低值。其他二羟基酚（间苯二酚和对苯二酚）在形成蓝色时不能模拟邻苯二酚的作用。间苯二酚是一种非常有效的愈创木酚过氧化抑制剂。提出了形成与琥珀色和蓝色相关的产物的可能方案。
In routine guaiacol assays for thyroid peroxidase and lactoperoxidase employing a newly purchased bottle of guaiacol from Aldrich Chemical Co., we were surprised to find the formation of a blue color instead of the expected amber color classically associated with this assay. This was observed also with horseradish, myelo-, and cytochrome c peroxidase. The blue color (Amax∼ 650 nm) was not formed with guaiacol reagents obtained from two other chemical companies, nor was it seen with a bottle of old Aldrich guaiacol that had been in use in the laboratory for more than 10 years. In the present investigation we provide evidence that formation of the blue color is closely associated with the presence of a low concentration of catechol (∼0.5 mol%) in the new Aldrich guaiacol reagent. Catechol itself, even in much higher concentration, is a very weak donor for peroxidase, forming a light pink color. The blue color in Aldrich new guaiacol is not formed to the exclusion of 470-nm-absorbing product(s). Formation of the latter is, however, inhibited, and use of Aldrich new guaiacol for assay leads to low values for peroxidase activity. Other dihydroxyphenols (resorcinol and hydroquinone) do not mimic the action of catechol in formation of the blue color. Resorcinol is a very potent inhibitor of peroxidation of guaiacol. Possible schemes are proposed for formation of the products that may be associated with the amber and blue colors.