Troyer G D, Goff C W, Klohs W D
J Histochem Cytochem. 1977 Nov;25(11):1247-53. doi: 10.1177/25.11.915244.
An electrophoretic study was performed to determine the number of isoenzymes of nucleoside diphosphatase in onion root extract. Five bands exhibiting nucleoside diphosphatase activity were detected when gels were incubated with inosine diphosphate, uridine diphosphate, guanosine diphosphate or cytidine diphosphate as substrates. These consisted of a single fast migrating band (band one), a group of three intermediate migrating bands (bands two, three and four) and a single slow migrating band (band five). Gels incubated with adenosine diphosphate, thiamine pyrophosphate, inosine monophosphate, guanosine monophosphate and cytidine monophosphate showed only two bands (bands one and five). Inhibitor studies showed that sodium fluoride inhibited bands one and five but not bands two, three and four. Conversely, 1% (v/v) glutaraldehyde inhibited bands two, three and four but did not inhibit bands one and five. These results suggest that two separate groups of onion nucleoside diphosphatase isoenzymes occur which have different substrate specificities and are selected against by certain inhibitors.
进行了一项电泳研究，以确定洋葱根提取物中核苷二磷酸酶同工酶的数量。当凝胶与肌苷二磷酸、尿苷二磷酸、鸟苷二磷酸或胞苷二磷酸作为底物一起孵育时，检测到五条显示核苷二磷酸酶活性的条带。这些条带包括一条快速迁移的单一条带（第一条带）、一组三条中间迁移的条带（第二条、第三条和第四条带）和一条缓慢迁移的单一条带（第五条带）。与腺苷二磷酸、硫胺素焦磷酸、肌苷一磷酸、鸟苷一磷酸和胞苷一磷酸一起孵育的凝胶仅显示两条条带（第一条带和第五条带）。抑制剂研究表明，氟化钠抑制第一条带和第五条带，但不抑制第二条、第三条和第四条带。相反，1%（v/v）戊二醛抑制第二条、第三条和第四条带，但不抑制第一条带和第五条带。这些结果表明，洋葱核苷二磷酸酶同工酶存在两个不同的组，它们具有不同的底物特异性，并被某些抑制剂所抑制。
