Molecular weights of protein multimers from polyacrylamide gel electrophoresis

A nonlinear relationship between polyacrylamide gel electrophoresis (PAGE) retardation coefficients (K_R) and molecular weights has been observed during analysis of several multimeric proteins. Although the deviation from linearity over a wide range of molecular weights is slight, it can lead to significant errors in the estimation of the sizes of individual multimers. Two alternative methods of analysis of PAGE results are compared and demonstrated to yield linear relationships for multimeric proteins having molecular weights as high as 900,000.