Wang X, Sirover M A, Anderson L E
Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607, USA.
Arch Biochem Biophys. 1999 Jul 15;367(2):348-53. doi: 10.1006/abbi.1999.1261.
Pea (Pisum sativum) chloroplastic glyceraldehyde-3-P dehydrogenase (EC 1.2.1.13) was tested for uracil DNA glycosylase activity. It was found that both the chloroplast and the recombinant subunit B dehydrogenases remove uracil from poly(dA[3H]dU). The glycosylase activity of the recombinant subunit B enzyme and that of a truncated form corresponding in length to subunit A were associated with the dehydrogenase activity in gel-filtration experiments. Both activities of the chloroplast enzyme were inhibited by antisera raised against recombinant subunit B, and both activities of the recombinant subunit B enzyme were inhibited by antisera raised against pea chloroplast glyceraldehyde-3-P dehydrogenase. Antisera raised against Escherichia coli uracil glycosylase did not affect the glycosylase activity of the recombinant subunit B enzyme. The glycosylase pH activity profile of the chloroplast dehydrogenase was unique. It is distinct from the dehydrogenase pH activity profile and from the pH activity profiles of other plant glycosylases. The glycosylase activity, but not the dehydrogenase activity, of the recombinant subunit B enzyme was inhibited by uracil. Pyridine nucleotides stimulated the glycosylase activity. To our knowledge this is the first example of a nonhuman glyceraldehyde-3-P dehydrogenase, and of an NADP-dependent glyceraldehyde-3-P dehydrogenase, that exhibits uracil glycosylase activity.
对豌豆（Pisum sativum）叶绿体甘油醛-3-磷酸脱氢酶（EC 1.2.1.13）进行了尿嘧啶DNA糖基化酶活性测试。结果发现，叶绿体和重组亚基B脱氢酶均可从聚（dA[3H]dU）中去除尿嘧啶。在凝胶过滤实验中，重组亚基B酶的糖基化酶活性以及与亚基A长度相对应的截短形式的糖基化酶活性与脱氢酶活性相关。叶绿体酶的两种活性均受到针对重组亚基B产生的抗血清的抑制，重组亚基B酶的两种活性均受到针对豌豆叶绿体甘油醛-3-磷酸脱氢酶产生的抗血清的抑制。针对大肠杆菌尿嘧啶糖基化酶产生的抗血清不影响重组亚基B酶的糖基化酶活性。叶绿体脱氢酶的糖基化酶pH活性曲线是独特的。它不同于脱氢酶pH活性曲线以及其他植物糖基化酶的pH活性曲线。尿嘧啶可抑制重组亚基B酶的糖基化酶活性，但不抑制其脱氢酶活性。吡啶核苷酸可刺激糖基化酶活性。据我们所知，这是首个表现出尿嘧啶糖基化酶活性的非人类甘油醛-3-磷酸脱氢酶以及首个依赖NADP的甘油醛-3-磷酸脱氢酶的例子。
