The mass of cellular retinoic acid binding protein I investigated by 13C depletion and mass spectrometry

The accuracy of mass spectrometry used to determine large molecular mass as proteins is often influenced by the isotopic compositions within a protein. Isotopic depletion is a powerful tool to resolve this problem. Using Fourier transform ion cyclotron resonance mass spectrometer, we investigated the 13C depleted cellular retinoic acid binding protein I, the measured mass accuracy is increased compared with the natural protein.