Table 2.

Site-selective ¹³C incorporation in histidine using glucose (G) or erythrose (E)

	1-13C G	2-13C G	1-13C E	2-13C E	3-13C E	4-13C E
His CO	31	7	1	0	0	3
His α	3	40	1	1	24	1
His β	0	0	9	34	1	0
His γ	n.d	n.d	n.d	n.d	n.d	n.d
His δ2	26	52	4	4	3	2
His ε1	37	8	1	1	3	14

Values are in %. Errors are estimated to 1% for ¹H bound ¹³C, 3% for others. 1% for non labeled positions is expected because of natural abundance of ¹³C