Ion Concentrations Surrounding the Myofilaments
My point of view is a radical departure from everybody elses. Cellular water has been looked at rather extensively. The more we look at it, the more we are confused. The kind of explanation I give here might have been overlooked in the past, but I think it provides clear and consistent physical interpretations. Let’s assume we have a dipole on the protein molecule in ionic water. The positive and negative charges are separated over a distance of about 100 Å. This is shown in Figure 1. The energy required to deposit these charges would come from ATP. As you can see right away the small region between charges experiences a very high electric field strength. If we have a significant potential gradient, then the electric field energy rapidly increases (Field Energy = 1/2 εE2). Note that it is proportional to the dielectric constant. Now, the dielectric constant of liquid water is about 80. When water freezes and becomes solid, the dielectric constant increases to about 90. This might sound odd because intuitively the dielectric constant of ice should be less than 80 due to more restricted rotational motion of water molecules. But actually, the opposite is true.
KeywordsDielectric Constant Field Line Debye Length Myosin Head Effective Dielectric Constant
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