Novel enzyme from rat liver that cleaves an ADP-ribosyl histone linkage.
Novel enzyme from rat liver that cleaves an ADP-ribosyl histone linkage.
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来自大鼠肝脏的新型酶，可裂解 ADP-核糖基组蛋白键。
DOI：
10.1073/pnas.75.5.2254
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发表时间：
1978
影响因子：
11.1
通讯作者：
O. Hayaishi
中科院分区：
文献类型：
--
作者：
H. Okayama;M. Honda;O. Hayaishi
从大鼠肝细胞浆中发现并部分纯化了一种能在ADP-核糖和组蛋白之间裂解键的新型酶。用45%饱和硫酸铵沉淀大鼠肝匀浆的105,000×g上清液，然后用DEAE-纤维素柱进行层析。该酶在0.2M的氯化钠溶液中呈单峰洗脱，与0.13M的聚腺苷二磷酸核糖水解酶有明显的分离。与后一种酶相反，这种新的酶催化了ADP-核糖与单一ADP-核糖化组蛋白H_2B中蛋白质部分之间的连接，但几乎没有(如果有的话)多聚ADP-核糖中的糖苷核糖基(1“-2‘)核糖键。纸层析和Dowex1柱层析分析表明，裂解产物中含有ADP-核糖部分，但与ADP-核糖不完全相同。现有证据表明，它要么是通过结构重排产生的改变的ADP-核糖分子，要么是与未知化合物相连的ADP-核糖本身。该酶的最适pH约为6.0，在5 mM ADP-核糖存在下，酶的抑制率为80-90%。
A novel enzyme that splits a bond between ADP-ribose and histone was discovered and partially purified from rat liver cytosol. The 105,000 X g supernatant of rat liver homogenate was precipitated by 45% saturated ammonium sulfate and then chromatographed on a DEAE-cellulose column. The enzyme activity was eluted in a single peak at about 0.2 M NaCl and clearly separated from poly(ADP-ribose) glycohydrolase which came out at 0.13 M NaCl. In contrast to the latter enzyme, this new enzyme catalyzed the spliting of a linkage between ADP-ribose and a protein portion in mono ADP-ribosylated histone H2B but little, if any, of the glycosidic ribosyl(1"-2') ribose bonds within poly(ADP-ribose). Analysis of the reaction product by paper chromatography and Dowex 1 column chromatography indicated that the split product contained the ADP-ribose moiety but was not exactly identical with ADP-ribose. Available evidence suggested that it was either an altered ADP-ribose molecule produced by a structural rearrangement or ADP-ribose itself linked to an unidentified compound. The enzyme had a pH optimum of about 6.0 and was inhibited by 80-90% in the presence of 5 mM ADP-ribose.