histidine

I was wondering why histidine < lysine < arginine are in this order of increasing basicity, if histidine has a more stable conjugate acid (protonated form) due to resonance?

Hi all, I have noted some inconsistencies about the properties of Histidine in my Kaplan study review. I was wondering if anyone had information that the AAMC would use themselves. I learned that histidine is considered a basic amino acid in graduate biochem, Kaplan agrees and disagrees...

what would be the correct choice? Under most biological conditions, however, histidine is considered to be a triprotic acid. This is due to the pKa of the _________ . A. Other nitrogen in the imidazole ring, that possesses a hydrogen but no charge being much lower than the pH values normally...