Ando T, Muraoka T, Okuda H
Anal Biochem. 1983 Apr 15;130(2):295-301. doi: 10.1016/0003-2697(83)90591-2.
A highly sensitive and accurate spectrophotometric method was developed for determination of guanase activity with guanine as substrate. The assay is based on the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone and N,N-diethylaniline. Xanthine formed from guanine by guanase is oxidized to uric acid and hydrogen peroxide by xanthine oxidase, and the hydrogen peroxide produced is determined by an oxidative-coupling reaction with 3-methyl-2-benzothiazolinone hydrazone and N,N-diethylaniline mediated by peroxidase. Formation of the indamine dye is greatly affected by the superoxide radical ion (O2-) and pH value. These problems can be overcome by separating the two reactions of hydrogen peroxide formation and color production and carrying out that color-producing reaction at pH 3.0. This method is very sensitive and accurate because the indamine dye has a very high molar extinction coefficient of 29,800. It can be used with various kinds of automatic analyzers such as a Hitachi, Olympus, or Technicon analyzer. Comparative studies showed that this method is more sensitive and reproducible than other methods. Furthermore, guanase activities determined by this method correlated well with those determined by the improved Ellis-Goldberg method. This method should be useful for measurement of guanase activity in banked blood for preventing transfusion hepatitis and could be valuable as a liver function test.
建立了一种以鸟嘌呤为底物测定鸟嘌呤酶活性的高灵敏度、准确的分光光度法。该测定基于3-甲基-2-苯并噻唑啉酮腙与N,N-二乙苯胺的氧化偶联反应。鸟嘌呤酶将鸟嘌呤转化为黄嘌呤，黄嘌呤氧化酶再将黄嘌呤氧化为尿酸和过氧化氢，产生的过氧化氢通过过氧化物酶介导的与3-甲基-2-苯并噻唑啉酮腙和N,N-二乙苯胺的氧化偶联反应进行测定。吲哚胺染料的形成受到超氧阴离子（O2-）和pH值的极大影响。通过分离过氧化氢生成和显色这两个反应，并在pH 3.0条件下进行显色反应，可以克服这些问题。该方法非常灵敏和准确，因为吲哚胺染料具有29800的非常高的摩尔消光系数。它可与各种自动分析仪如日立、奥林巴斯或Technicon分析仪一起使用。比较研究表明，该方法比其他方法更灵敏且可重复。此外，用该方法测定的鸟嘌呤酶活性与用改进的埃利斯-戈德堡方法测定的结果相关性良好。该方法对于测定库存血中鸟嘌呤酶活性以预防输血后肝炎应是有用的，并且作为肝功能测试可能具有价值。
