Taurog A, Dorris M L, Guziec F S
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235.
Anal Biochem. 1992 Sep;205(2):271-7. doi: 10.1016/0003-2697(92)90434-9.
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 approximately 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 (approximately 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.
在使用从奥德里奇化学公司新购的愈创木酚对甲状腺过氧化物酶和乳过氧化物酶进行常规检测时，我们惊讶地发现形成的是蓝色而非该检测通常预期的琥珀色。用辣根过氧化物酶、髓过氧化物酶和细胞色素c过氧化物酶检测时也观察到了这种情况。从其他两家化学公司获得的愈创木酚试剂不会形成蓝色（最大吸收波长约为650nm），在实验室使用了10多年的一瓶旧的奥德里奇愈创木酚也未出现这种情况。在本研究中，我们提供证据表明蓝色的形成与新的奥德里奇愈创木酚试剂中低浓度（约0.5mol%）儿茶酚的存在密切相关。即使儿茶酚浓度高得多，它本身也是过氧化物酶的非常弱的供体，形成浅粉色。奥德里奇新愈创木酚中的蓝色并非在不形成470nm吸收产物的情况下形成。然而，后者的形成受到抑制，使用奥德里奇新愈创木酚进行检测会导致过氧化物酶活性值偏低。其他二羟基酚（间苯二酚和对苯二酚）在蓝色形成过程中不会模拟儿茶酚的作用。间苯二酚是愈创木酚过氧化的非常有效的抑制剂。提出了可能与琥珀色和蓝色相关的产物形成的可能方案。
