Desmarais Y, Ménard L, Lagueux J, Poirier G G
Laboratoire du Métabolisme du poly ADP-ribose, Endocrinologie Moléculaire, CHUL, Ste-Foy, Canada.
Biochim Biophys Acta. 1991 Jun 24;1078(2):179-86. doi: 10.1016/0167-4838(91)99007-f.
We have characterized the effect of poly(ADP-ribose) polymerase automodification on the enzyme's activities, which include poly(ADP-ribose) synthesis and NADase activity. The apparent Km of the enzyme for NAD+ during polymer synthesis is higher than the one measured for alternate NADase activity. Furthermore, we have found that there are 28 automodification sites, in contrast to the 15 sites (postulated to be on the 15 glutamic acids) reported to be present in the automodification domain. For the first time, we show that some of these acceptor sites are outside the reported automodification domain (15 kDa); we demonstrate automodification in the NAD+ binding domain (55.2 kDa) and the DNA binding domain (42.5 kDa). We have analyzed the relationship between the number of sites modified on poly(ADP-ribose) polymerase and its effect on the polymerization activity and its alternate NADase activity. Automodification greatly altered both enzyme activities, decreasing both polymer synthesis and alternate NADase activity.
我们已经表征了聚（ADP - 核糖）聚合酶自身修饰对该酶活性的影响，这些活性包括聚（ADP - 核糖）合成和NAD酶活性。在聚合物合成过程中，该酶对NAD⁺的表观Km高于为交替NAD酶活性测定的值。此外，我们发现有28个自身修饰位点，与报道的自身修饰结构域中存在的15个位点（假定位于15个谷氨酸上）形成对比。我们首次表明，其中一些受体位点在报道的自身修饰结构域（15 kDa）之外；我们在NAD⁺结合结构域（55.2 kDa）和DNA结合结构域（42.5 kDa）中证明了自身修饰。我们分析了聚（ADP - 核糖）聚合酶上修饰位点的数量与其对聚合活性和交替NAD酶活性的影响之间的关系。自身修饰极大地改变了这两种酶活性，降低了聚合物合成和交替NAD酶活性。
