How to estimate the position of the mistranslated proteins on a two‐dimensional gel electrophoregram

A method for the estimation of amino acid misincorporation into ribosomal proteins is presented. The method is based on the observation that the horizontal mobility of the 52 E. coli ribosomal proteins is proportional to Q/N, where Q is the calculated charge of the protein and N designates the number of residues in the protein. Thus the mobility change caused by a change in charge, such as the replacement of arginine by cysteine, can be predicted and the gel fractions used for scintillation counting cut accordingly. The gel system used in this paper was not the O'Farrell system but a ribosomal system whose first dimension was run at pH 5 in the presence of 8 M urea.