Figure 4 of
Takemoto, Mol Vis 5:2, 1999.
Figure 4. Quantitation of glutamine-6 deamidation
Resolution of amidated and deamidated forms of tryptic peptides corresponding to sequence 1-11 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 23 - 30% (v/v) acetonitrile in 0.1% (v/v) trifluoroacetic acid over a period of 60 min, followed by a linear gradient of 30 - 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). Large open arrows designate elution of amidated peptide AcMDVTIQHPWFK, small open arrows designate elution of amidated peptide AcMDVTIQHPWFK, large closed arrows designate elution of deamidated peptide AcMDVTIEHPWFK, small closed arrows designate elution of deamidated peptide AcMDVTIEHPWFK.