Maki H, Yamagishi K, Sato T, Ogura N, Nakagawa H
Department of Agricultural Chemistry, Faculty of Horticulture, Chiba University, Matsudo, Chiba 271, Japan.
Plant Physiol. 1986 Nov;82(3):739-41. doi: 10.1104/pp.82.3.739.
An enzyme-linked immunosorbent assay permitting the determination of nanogram quantities of nitrate reductase (NR) in cultured spinach cells has been developed and used for studies of the mechanism by which NR activity is regulated as a function of culture age. When 8-day old spinach cells were transferred to fresh medium, NR activity increased markedly in 2 days and thereafter decreased gradually until it became undetectable on the 10th day after the transfer. Determination of the amounts of NR by the immunosorbent assay indicated that the unique alteration of NR activity could be accounted for by the concomitant change in the amount of NR protein. Immunoblotting analysis of the subunit of NR also supported this result. It is concluded that the regulation of NR in spinach cells as a function of culture age is mediated by changes in the amount of the enzyme protein rather than by activation and inactivation of the preexisting proteins.
已开发出一种酶联免疫吸附测定法，可测定培养的菠菜细胞中纳克量的硝酸还原酶（NR），并用于研究NR活性随培养时间变化而受到调节的机制。当8日龄的菠菜细胞转移到新鲜培养基中时，NR活性在2天内显著增加，此后逐渐下降，直到转移后第10天无法检测到。通过免疫吸附测定法测定NR的量表明，NR活性的独特变化可由NR蛋白量的相应变化来解释。对NR亚基的免疫印迹分析也支持了这一结果。得出的结论是，菠菜细胞中NR随培养时间的调节是由酶蛋白量的变化介导的，而不是由现有蛋白质的激活和失活介导的。
