Problem

Amino Acids Can Act as Both Acids and BasesREFLECT AND APPLY Based on the information in T...

Amino Acids Can Act as Both Acids and Bases

REFLECT AND APPLY Based on the information in Table, is there any amino acid that could serve as a buffer at pH 8? If so, which one?

Table pKa Values of Common Amino Acids

Acid	α-COOH	α-NH3+	RH orRH+
Gly	2.34	9.60
Ala	2.34	9.69
Val	2.32	9.62
Leu	2.36	9.68
Ile	2.36	9.68
Ser	2.21	9.15
Thr	2.63	10.43
Met	2.28	9.21
Phe	1.83	9.13
Trp	2.38	9.39
Asn	2.02	8.80
Gln	2.17	9.13
Pro	1.99	10.6
Asp	2.09	9.82	3.86*
Glu	2.19	9.67	4.25*
His	1.82	9.17	6.0*
Cys	1.71	10.78	8.33*
Tyr	2.20	9.11	10.07
Lys	2.18	8.95	10.53
Arg	2.17	9.04	12.48
*For these amino acids, the R group ionization occurs before the α-NH+ ionization.