IV COOH HNOH COO HNCH CH COO HNCH CH PKR 11 00 COO HN-CH ex PK 92 - p1 15 The conjugate acid (protonated form of the imidazole side chain in histidine has a pk, of -6 when determined in aqueous solution. At pH 7, a majority of histidine exists in its deprotonated base form (ll in the scheme). = pH - pka From the Henderson-Hasselbalch equation, one can tell that at pH 7, what is the ratio of pur to ? log Answer: Roughly, how many % of histidine molecules eest in the form of li at pH 7, while the rest exist in the form of Answer: Between it and I can serve as a general acid while is a good nudeophile Disregard the s-amino and the carboxylate groups) IlI can also serve as a general