Why is the pKa value lower?
pKa value is different because alanine has an amino group.amino group has nitrogen which is more electronegative then carbon so it attracts electrons from carbon forming a permanent dipole.when carboxylic group in alanine loses a proton a negative carboxylate anion is formed.negativecharge is stabilised by the amino group which attracts the negative charge.for the same reason ClCH2COOH is more acidic then CH3COOH.
