摘要
利用ＮＡＤ激酶法和平衡透析法，作者研究了不同ｐＨ条件对Ｃａ２＋，钙调素（ＣａＭ）的结合能力及ＣａＭ激活ＮＡＤ激酶的影响．结果发现：Ｈ＋不仅能降低Ｃａ２＋与ＣａＭ的结合能力而且还能显著抑制ＣａＭ对ＮＡＤ激酶的激活．本实验证实了酸性条件下不利于ＣａＭ的活性状态的转变，即ｐＨ值低时激活ＣａＭ需要更多的Ｃａ２＋．此研究结果为植物胞外钙调素调节机理的研究提供了一个方面的解释。
It was normally been considered that calmodulin is an entracellular calcium receptor protein,and play important roles in signal transduction pathway of eukaryocyte cells.However,nearly 15 years' works in our lab have proved that plant calmodulin not only exits extracellularly but also has important extracellular functions.Especially in recent years,we have got great process in studying the new functions and the signal transduction pathway of plant extracellular calmodulin.With the research going on in depth,We have to face the problem:how does extracellular calmodulin be regulated when it was in the high concentration calcium circulation of plant cell wall?Here,by using the methods of equilibrium dialyze and activation of NAD kinase,we have studied the influence of different pH on the binding of calcium to calmodulin and the activation effects of calmodulin to its target enzyme.It was founded that besides decreasing the binding affinity of calcium to calmodulin,H + could also inhibit calmodulin active NAD kinase.When pH decrease 2 units,it could decrease the sensation of calmodulin to calcium concentration to 10 folds when it active NAD kinase.We suggest that this phenomenon might play some role on the regulation mechanism of extracellular calmodulin.Other possible regulation mechanisms which were distinguishable to intracellular calmodulin were also discussed.
出处
《河北师范大学学报（自然科学版）》
CAS
1999年第1期106-111,共6页
Journal of Hebei Normal University：Natural Science
基金
国家自然科学基金
河北省自然科学基金
