In carbonic anhydrase, its side chain can be used to shuttle protons away from a water molecule to activate the enzyme again.
In a recent study, a mutation in the gene encoding for the decarboxylase of this molecule has been linked to the modulation of Tourette's Syndrome. In Neurospora crassa, this molecule can be converted into ergothioneine. In carbonic anhydrase, its side chain can be used to shuttle protons away from a water molecule to activate the enzyme again. In the zinc finger motif, two cysteine residues and two examples of this amino acid are used to trap the zinc ion. This amino acid's function in catalytic triads is to abstract a proton from serine, threonine, or cysteine, activating any of those amino acids as a nucleophile. It is both aromatic and basic because of its imidazole side chain. For 10 points, name this amino acid that can be decarboxylated to form histamine.
In a recent study, a mutation in the gene encoding for the decarboxylase of this molecule has been linked to the modulation of Tourette's Syndrome.
{histidine} [prompt on His]