Aoyagi K, Nakamoto H
Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720.
Plant Physiol. 1985 Jul;78(3):661-4. doi: 10.1104/pp.78.3.661.
Mesophyll protoplasts and bundle sheath strands were isolated from maize leaves. Light microscopic observation showed the preparations were pure and without cross contamination. Protein blot analysis of mesophyll and bundle sheath cell soluble protein showed that the concentration of pyruvate orthophosphate dikinase (EC 2.7.9.1) is about one-tenth as much in the bundle sheath cells as in mesophyll cells, but about eight times greater than that found in wheat leaves, on the basis of soluble protein. Phosphoenolpyruvate carboxylase (EC 4.1.1.31) was barely detectable in the bundle sheath cells, while ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) and NADP-dependent malic enzyme (EC 1.3.1.37) were exclusively present in the bundle sheath cells and were absent in the mesophyll cells. Whereas pyruvate, Pi dikinase was previously considered localized only in mesophyll cells of C(4) plants, these results clearly demonstrate the presence of appreciable quantities of the enzyme in the bundle sheath cells of the C(4) species maize.
从玉米叶片中分离出叶肉原生质体和维管束鞘细胞束。光学显微镜观察表明，制备物纯净且无交叉污染。对叶肉细胞和维管束鞘细胞可溶性蛋白进行蛋白质印迹分析，结果显示，基于可溶性蛋白，丙酮酸磷酸双激酶（EC 2.7.9.1）在维管束鞘细胞中的浓度约为叶肉细胞中的十分之一，但比在小麦叶片中发现的浓度高约八倍。磷酸烯醇式丙酮酸羧化酶（EC 4.1.1.31）在维管束鞘细胞中几乎检测不到，而核酮糖-1,5-二磷酸羧化酶（EC 4.1.1.39）和依赖NADP的苹果酸酶（EC 1.3.1.37）仅存在于维管束鞘细胞中，叶肉细胞中不存在。尽管丙酮酸磷酸双激酶以前被认为仅存在于C4植物的叶肉细胞中，但这些结果清楚地表明，在C4植物玉米的维管束鞘细胞中存在相当数量的该酶。
