Question

The factor which does not affect pKa value of an amino acid is _________

(a) The loss of charge in the α-carboxyl and α-amino groups

(b) The interactions with other peptide R groups

(c) Other environmental factors

(d) Molecular weight

I have been asked this question by my college director while I was bunking the class.

My question is taken from Peptides and Proteins in section Amino Acids, Peptides and Proteins of Biochemistry

Answer 1

Correct choice is (d) Molecular weight

To elaborate: The loss of charge in the α-carboxyl and α-amino groups, the interactions with other peptide R groups and other environmental factors can affect the pKa.