Biochemistry – Question 1
At physiological pH, the most stable amino acid is:
a) Histidine
b) Lysine
c) Arginine
d) Leucine
Answer and Explanation
a) Histidine
Histidine plays unique roles in enzymatic catalysis.
The pK of its imidazole proton permits it to function at neutral pH or physiological pH as either a base or an acid catalyst.
Ref: Harper’s Illustrated Biochemistry, 31st Edition and Page-20
