Department of Horticulture, Purdue University, West Lafayette, Indiana 47907.
Plant Physiol. 1991 May;96(1):245-50. doi: 10.1104/pp.96.1.245.
Tobacco (Nicotiana tabacum L. var Wisconsin 38) cells that are adapted to 428 millimolar NaCl accumulate proline mainly due to increased synthesis from glutamate. These cells were used to evaluate the possible role of Delta(1)-pyrroline-5-carboxylate reductase in the regulation of proline biosynthesis. No increase in the specific activity of Delta(1)-pyrroline-5-carboxylate reductase in crude extracts throughout the growth cycle was observed in NaCl-adapted cells compared to unadapted cells. The enzyme from both cell types was purified extensively. On the basis of affinity for the substrates NADPH, NADH, and Delta(1)-pyrroline-5-carboxylate, pH profiles, chromatographic behavior during purification, and electrophoretic mobility of the native enzyme, the activities of the enzyme from the two sources were similar. These data suggest that the NaCl-dependent regulation of proline synthesis in tobacco cells does not involve induction of pyrroline-5-carboxylate isozymes or changes in its kinetic properties.
适应 428 毫摩尔/升 NaCl 的烟草（Nicotiana tabacum L. var Wisconsin 38）细胞主要通过谷氨酸合成增加来积累脯氨酸。这些细胞被用于评估 δ（1）-吡咯啉-5-羧酸还原酶在脯氨酸生物合成调节中的可能作用。与未适应细胞相比，在 NaCl 适应细胞的整个生长周期中，粗提物中 δ（1）-吡咯啉-5-羧酸还原酶的比活性没有增加。两种细胞类型的酶都得到了广泛的纯化。基于对 NADPH、NADH 和 δ（1）-吡咯啉-5-羧酸的底物亲和力、pH 曲线、纯化过程中的色谱行为以及天然酶的电泳迁移率，两种来源的酶的活性相似。这些数据表明，烟草细胞中脯氨酸合成的 NaCl 依赖性调节不涉及吡咯啉-5-羧酸同工酶的诱导或其动力学特性的变化。
