醛缩酶与含肌动蛋白丝的结合。相互作用的定量重新评估。
Binding of aldolase to actin-containing filaments. Quantitative reappraisal of the interactions.
作者信息
Masters C J, Winzor D J, Nichol L W
出版信息
Biochem J. 1981 Apr 1;195(1):297-9. doi: 10.1042/bj1950297.
Previously reported results of equilibrium-partition experiments on the interaction of aldolase with actin-containing filaments [Walsh, Winzor, Clarke, Masters & Morton (1980) Biochem. J. 186, 89-98] have been subjected to a more rigorous theoretical analysis involving consideration of the consequences of cross-linking interactions between enzyme and filament. The experimental results obtained with F-actin-tropomyosin are best described by a model with one binding site per heptameric repeat unit of filament and a value of 39000 M-1 for the site binding constant, k. Similar analyses of the influence of Ca2+ on aldolase binding to F-actin--tropomyosin--troponin substantiate the existence of two equivalent binding sites (k = 14900 M-1) for the enzyme on each repeat unit of the thin filament. The Ca2+-sensitivity of this interaction reflects either a decrease in the strength of aldolase binding to these two sites (k = 8200 M-1) or the elimination of one site.
先前报道的关于醛缩酶与含肌动蛋白丝相互作用的平衡分配实验结果[沃尔什、温佐尔、克拉克、马斯特斯和莫顿（1980年），《生物化学杂志》186卷，89 - 98页]已经接受了更严格的理论分析，其中考虑了酶与丝之间交联相互作用的后果。用F - 肌动蛋白 - 原肌球蛋白获得的实验结果最好用一个模型来描述，该模型中每个七聚体重复单元的丝有一个结合位点，位点结合常数k的值为39000 M⁻¹。对Ca²⁺对醛缩酶与F - 肌动蛋白 - 原肌球蛋白 - 肌钙蛋白结合影响的类似分析证实，在细肌丝的每个重复单元上，酶存在两个等效的结合位点（k = 14900 M⁻¹）。这种相互作用对Ca²⁺的敏感性反映出要么醛缩酶与这两个位点的结合强度降低（k = 8200 M⁻¹），要么一个位点被消除。
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