. Author manuscript; available in PMC: 2013 Aug 1.

Published in final edited form as: J Am Chem Soc. 2012 Jul 17;134(30):12658–12667. doi: 10.1021/ja3039486

Table 1.

Frequency of various features in 2D IR spectra and calculated percent deamidation from HPLC.

Label	Frequency unmodified peptide isotope peak (cm⁻¹)	Frequency unmodified peptide unlabeled peak (cm⁻¹)	Frequency deamidated peptide isotope peak (cm⁻¹)	Frequency deamidated peptide unlabeled peak (cm⁻¹)	Frequency unmodified peptide unlabeled peak without coupling (cm⁻¹)⁵⁶	% Deamidated (from HPLC)
A8	1590	1618	~1600	1617	1600 ±3	85 ±5
A13	1579	1615	~1595	1620	1598 ±1	95 ±5
L16	1581	1617	1585	1619	1588 ±1	69 ±5
L27	1577	1614	NA	1620	1598±2	64 ±5