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. Author manuscript; available in PMC: 2020 Mar 1.

Published in final edited form as: J Am Soc Mass Spectrom. 2018 Nov 12;30(3):448–458. doi: 10.1007/s13361-018-2093-9

Table 2.

Reaction rate constants for 18 amino acids that show apparent first order rection kinetics ^a

	l-AA		d-AA
l-Mar-AA	k (hr⁻¹)	4×t_1/2 (hr)^b	k (hr⁻¹)	4×t_1/2 (hr)^b	Max (4×t_1/2) (hr)^b	Log₂ (k_d/k_l)
Gly	2.92	0.95			0.95
Ala	0.99	2.81	1.40	1.98	2.81	0.50
Ser	0.46	6.02	0.90	3.08	6.02	0.97
Pro	40	0.29	22	0.12	0.29	−0.86
Val	1.90	1.46	2.92	0.95	1.46	0.62
Thr	0.17	16.31	0.29	9.56	16.72	0.77
Ile	2.55	1.09	3.01	0.92	1.09	0.24
Leu	1.88	1.48	2.05	1.35	1.48	0.12
Asn	0.84	3.30	0.92	3.02	9.86	0.13
Asp	0.31	8.94	0.51	5.44	8.97	0.72
Gln	1.11	2.49	2.11	1.32	2.49	0.93
Glu	0.36	7.70	0.56	4.95	7.69	0.64
Met	1.27	2.18	1.35	2.05	2.18	0.09
Phe	4.41	0.63	3.03	0.92	0.92	−0.54
Arg	1.25	2.22	1.49	1.86	2.9	0.25
Trp	7.35	0.38	4.49	0.62	0.62	−0.71
Lys (Bis)	0.93	2.98	0.92	3.01	3.02	−0.02
Cys₂ (Bis)	0.78	3.56	0.61	4.55	4.57	−0.35

^a

For Tyr and His, which show multistep kinetics, see Figure 4.

^b

4×t_1/2 is used as indicator of near quantitative (95%) completion of the derivatization reaction.