label: D-histidine + S-adenosyl-L-methionine = (2S)-2-amino-4-{[(1R)-1-carboxy-2-(1H-imidazol-4-yl)ethyl]amino}butanoate + S-methyl-5'-thioadenosine + H(+)
label_lc: d-histidine + s-adenosyl-l-methionine = (2s)-2-amino-4-{[(1r)-1-carboxy-2-(1h-imidazol-4-yl)ethyl]amino}butanoate + s-methyl-5'-thioadenosine + h(+)