Q.
Which of the nitrogen of histidine is first protonated?
A) $\alpha$
B) $\beta$
C) Both (a) and (b)
D) None of these
Explanation
(b)
Protonation of $\beta$-N leads to imidazolium ion, which is stabilized by two equivalent resonating structures
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.