Department of Botany, The Ohio State University, 43210, Columbus, Ohio, USA.
Planta. 1976 Jan;130(3):295-301. doi: 10.1007/BF00387836.
Using recently developed techniques, we have investigated the binding of (45)Ca(2+) to membrane preparations from corn (Zea mays L) and oat (Avena sativa L) coleoptile tissue. Scatchard plot analysis reveals at least two Ca(2+)-binding sites in each tissue, a high affinity binding site (K m=7.7×10(-7) M, n=6.9×10(-10) mol·0.5 g f.w.(-1) in corn, K m=4.93×10(-6) M, n=2.29×10(-9) mol·0.5 g f.w.(-1) in Avena) and a low affinity binding site (K m=9.01×10(-5) M, n=5.4×10(-8) mol·0.5 g f.w.(-1) in corn; K m=1.03×10(-4) M, n=3.40×10(-8) mol·0.5 g f.w.(-1) in Avena). There is also some evidence of a third, lower affinity binding site in each tissue, especially corn.More detailed studies with corn coleoptile homogenates show that they contain a potent dialyzable inhibitor of Ca(2+) binding. Monovalent cations were observed to be ineffective as inhibitors of Ca(2+) binding in corn. However, of six divalent cations tested, all were capable of strong inhibition of Ca(2+)-binding and there appeared to be a relationship between size of the atomic radius of the ion and potency as an inhibitor of calcium binding.
利用最近开发的技术，我们研究了（45）Ca（2+）与玉米（Zea mays L）和燕麦（Avena sativa L）胚芽鞘组织膜制剂的结合。Scatchard 图分析表明，每种组织中至少存在两个 Ca（2+）结合位点，一个高亲和力结合位点（K m=7.7×10（-7）M，n=6.9×10（-10）mol·0.5 g f.w.（-1）在玉米中，K m=4.93×10（-6）M，n=2.29×10（-9）mol·0.5 g f.w.（-1）在燕麦中）和一个低亲和力结合位点（K m=9.01×10（-5）M，n=5.4×10（-8）mol·0.5 g f.w.（-1）在玉米中；K m=1.03×10（-4）M，n=3.40×10（-8）mol·0.5 g f.w.（-1）在燕麦中）。每个组织中也有一些证据表明存在第三个、亲和力更低的结合位点，尤其是玉米。对玉米胚芽鞘匀浆的更详细研究表明，它们含有一种有效的钙结合可透析抑制剂。单价阳离子被观察到对玉米中 Ca（2+）结合没有抑制作用。然而，在所测试的六种二价阳离子中，所有阳离子都能够强烈抑制 Ca（2+）结合，并且似乎存在离子原子半径大小与钙结合抑制能力之间的关系。
