Practice question

One-dimensional electrophoresis resolves proteins by single parameter, typically molecular mass in SDS-PAGE, leading to significant spot overlap in whole cell lysates containing thousands of polypeptides with similar sizes. Two-dimensional electrophoresis combines isoelectric focusing followed by SDS-PAGE, separating first by isoelectric point and subsequently by molecular weight, providing orthogonal resolution. This dramatically increases peak capacity and resolving power, revealing post-translational isoforms, modified variants and low-abundance species that co-migrate in 1D systems. Isoelectric focusing, native PAGE, or SDS-PAGE alone provide only one-dimensional information, insufficient for proteome complexity.