The pKA of histidine in a protein active site where it is next to an aspartate or glutamate would be____________ the pKa of free histidine solution
higher, lower, no different
Is it higher??
To answer this question, we need to know what pKa means.
pKa = -log Ka
So, what does that tell us? What is Ka? That is the dissociation or ionization constant for an acid.
HA + H2O <------> A- + H3O+
Ka = [A-][H3O+]/[HA]
Therefore, the more that the acid dissociates in water, the larger the Ka. The Ka is a measure of the degree of ionization of an acid in water. A ...