Figure 11. The ion cyclotron resonance Fourier transform mass spectrometry spectrum of the soluble fraction of an eye lens from a 1-month-old human subject

The lens was homogenized in 1.0 ml of 0.02 M phosphate buffer at pH 7.0 with 0.001 M EDTA, centrifuged to remove the insoluble protein fraction, and desalted by repeated H₂O centrifugal washing over a 3,000 Dalton filter. It was then diluted with 49/49/2 H₂O/methanol/acetic acid before being introduced into the mass spectrometer. The separations shown were carried out in the ICR FTMS cell. The labeled crystallin fractions are the ten most prevalent proteins known to exist in the young human lens [33].