Histidine is an amino acid containing extra nitrogen.
Like all amino acids, it has an amino group (-NH2
) - blue with 2 white balls - at one end, and a carboxylic acid group (-COOH) - grey, connected to red, and red and white - at the other end. These groups are used to link onto other amino acids by peptide bonds. Between these is the
α- (alpha) carbon
to which the 'R' group is attached.
Its 'R' group has an imidazole ring containing 2 nitrogen atoms at the other end of the molecule
so it has extra basic characteristics as well as aromaticity
Histidine is a precursor to histamine which is involved in local immune responses and triggers the inflammatory response, amongst other roles.
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