Figure 3 of
Takemoto, Mol Vis 5:2, 1999.
Figure 3. Quantitation of glutamine-50 deamidation
Resolution of amidated and deamidated forms of tryptic peptides corresponding to sequence 50-54 of [alpha]-A crystallin. The tryptic digest was resolved on a C18 reverse phase column (4.6 mm x 250 mm, Vydac) using a linear gradient of 12 - 17% (v/v) acetonitrile in 0.1% (v/v) trifluoroacetic acid over a period of 60 min, followed by linear gradient of 17 - 60% (v/v) acetonitrile in 0.1% (v/v) trifluoroacetic acid over a period of 5 min. Only the part of the elution profile showing peptides of interest is shown. Top, digest from 71 yr old normal lens (71N); middle, digest from 65 yr old cataractous lens (65C) with opacification of the nucleus; bottom, synthetic peptide standards (STND). Open arrows designate elution of amidated peptide QLSFR, closed arrows designate elution of deamidated peptide ELSFR.