Horizontal carryover of proteins on one-dimensional polyacrylamide gels may jeopardize gel-enhanced liquid chromatography mass spectrometry proteomic interpretations.

Abstract Mass spectrometric identification of gel-separated proteins is a cornerstone of many proteomic efforts. Often the protein compositions of two neighboring lanes (typically representing the experiment and control) are compared assuming that proteins are separated only in a vertical dimension and do not spread horizontally. However, we noticed that horizontal protein spreading commonly occurs on one-dimensional polyacrylamide gels and might lead to a misleading judgment regarding the presence or absence of particular proteins even in the distantly spaced lanes. Therefore, we suggest that experimental and control samples should always be loaded on separate gels.