Apparatus for direct counting of beta-rays from two-dimensional protein gels: measurement of changes in protein synthesis due to changes in density of Chinese hamster ovary cells.

A method is described for scanning two-dimensional protein gels that utilizes direct counting of beta-rays instead of autoradiography. The methodology is compared with autoradiographic results and data are presented demonstrating changed patterns of protein synthesis accompanying changes in cell density. The method is rapid and permits identification of differences in protein abundance of approximately 10% for a substantial fraction of the more prominent proteins. A modulation effect of greater than 5 standard deviations is shown to occur for an appreciable number of the proteins that accompany the inhibition of cell growth due to contact inhibition. The method promises application to a variety of biochemical and genetic problems designed to delineate changes in protein synthesis accompanying changes in genome, molecular environment, history, and state of differentiation of the cell populations studied.