Why do the amino groups in EDTA deprotonate first, in contrast to amino acids?
The carboxylates deprotonate first followed by the amines.  The pKa values for the carboxylates ar 0.0, 1.5, 2.0, and 2.66.  The amines have pKa values of 6.16 and 10.24.  Ref. Harris.  Quantitative Chemical Analysis.