Answer is: the ionized state of the carboxyl group is COO⁻. Physiological pH is 7,4 and carboxyl group in the R group has pKa = 3,7. Since this pKa is lower than phys<span>iological pH of 7,4, carboxyl group (COOH) will lost proton, and because of that it will be deprotonated and will have negative charge. </span>Aspartic acid<span> is an α-amino acid that is used in the biosynthesis of proteins.</span>
