Andersson T, Drakenberg T, Forsén S, Thulin E
Eur J Biochem. 1982 Sep 1;126(3):501-5. doi: 10.1111/j.1432-1033.1982.tb06808.x.
The exchange rates of Ca2+ ions to the two classes of sites on calmodulin have been determined from the temperature dependence of the 43Ca NMR line width. The exchange rates were found to differ by a factor of about 40 at room temperature. The apparent pK value for one of these classes was estimated from the pH dependence of the 43Ca line width. The pK values of the two-high-affinity sites were found to differ about 0.1-1. Zn2+ ions were shown to bind to calmodulin and affect the exchange rates of Ca2+ and Cd2+ for all four sites.
已根据43Ca NMR线宽的温度依赖性确定了钙调蛋白上两类位点的Ca2+离子交换率。发现在室温下，这两种交换率相差约40倍。其中一类位点的表观pK值是根据43Ca线宽的pH依赖性估算得出的。发现两个高亲和力位点的pK值相差约0.1 - 1。研究表明，Zn2+离子可与钙调蛋白结合，并影响所有四个位点的Ca2+和Cd2+交换率。
