Table 2.

Comparison of H/D exchange monitored by mass spectrometry^a and NMR measurements.

			Number of Amidesb
Region	IκBα peptides a	Total amides	Free	Free (IκBα(67-206))	Bound	Bound
			Mass (after 2 mins)	NMR (after 30 mins)	Mass (after 2 mins)	NMR (after 30 mins)
ANK 1	66-80	14	2.0	1	4.9	1
	79-91	12	5.6	6	-	9
	92-103	11	4.0	5	3.6	5
ANK 2	104-117	12	9.8	7	9.4	2
	105-117	11	8.6	6	8.0	2
ANK 3	137-150	12	10.5	8	10.6	1
	140-150	9	7.4	6	7.4	1
	142-150	7	6.1	5	5.8	1
	158-176	17	7.3	4	6.9	1
ANK 4	177-187	10	6.2	1	7.0	3
	188-197	9	4.8	5	6.4	1
	188-201	13	8.3	7	8.2	4
ANK 4/5	201-220	18	3.9	4 [201-206] c	12.3	9
	201-223	20	2.7	4 [201-206] c	13.3	12
	202-223	19	2.3	3 [202-206] c	12.7	11
ANK 6	242-257	14	0	-	10.9	11
	243-257	13	0	-	10.6	10
	258-272	13	0	-	1.3	1
	258-274	15	0	-	2.0	1

^aModified from table 1 of the paper by Truhlar et al.²¹

^bNumber of amides that remain unexchanged, calculated from the mass increase at the 2-minute time point²¹ or from cross peaks remaining in the NMR spectrum at the earliest time point.

^cConstruct ends at residue 206.