Dalling M J, Hucklesby D P, Hageman R H
Department of Agronomy, University of Illinois, Urbana, Illinois 61801.
Plant Physiol. 1973 Mar;51(3):481-4. doi: 10.1104/pp.51.3.481.
Nitrite reductase from green leaves of corn (Zea mays L.) is eluted from a diethylaminoethyl-cellulose column in one peak of activity by a chloride gradient, while nitrite reductase from scutellum tissue is resolved into two peaks of activity, apparently representing two forms of the enzyme NiR1 and NiR2. One of these (NiR2) elutes at the same concentration of chloride as the leaf nitrite reductase. Roots and etiolated shoots also exhibited both forms of the enzyme, however, lesser amounts of NiR1 is extractable from these tissues than from scutellum. Comparison of green leaf nitrite reductase with NiR2 from scutellum tissue shows similar or identical properties with respect to molecular weight, isoelectric point, electron donor requirements, inhibition properties, pH optima, thermal stability, and pH tolerance. The significance of these similarities in relation to probable differences in the biochemical mechanism of nitrite reduction between leaf and scutellum tissues is discussed. Although ferredoxin is considered, with some reservations, to be the electron donor for nitrite reductase in green tissue, the reductant for nongreen tissue is not known. The possibility that nitrite reductases from green and non-green tissues uses the same electron donor, in vivo, is considered.
玉米（Zea mays L.）绿叶中的亚硝酸还原酶通过氯化物梯度从二乙氨基乙基纤维素柱上以一个活性峰洗脱，而盾片组织中的亚硝酸还原酶则被分离为两个活性峰，显然代表了两种形式的酶NiR1和NiR2。其中一种（NiR2）在与叶片亚硝酸还原酶相同的氯化物浓度下洗脱。根和黄化苗也表现出这两种形式的酶，然而，从这些组织中可提取的NiR1量比从盾片中少。将绿叶亚硝酸还原酶与盾片组织中的NiR2进行比较，结果表明在分子量、等电点、电子供体需求、抑制特性、最适pH值、热稳定性和pH耐受性方面具有相似或相同的特性。讨论了这些相似性与叶片和盾片组织中亚硝酸还原生化机制可能存在的差异之间的关系。尽管有些保留地认为铁氧还蛋白是绿色组织中亚硝酸还原酶的电子供体，但非绿色组织的还原剂尚不清楚。考虑了绿色和非绿色组织中的亚硝酸还原酶在体内使用相同电子供体的可能性。
