Semi-dry PhastTransfer detection of biotinylated cell surface molecules.

The PhastTransfer system is a semi-dry electrophoretic unit designed to optimize the transfer of small amounts of protein. Because of its efficiency, we adapted the PhastTransfer system for the detection of labeled membrane molecules. Biotin was used as the membrane molecule label because it permitted the long-term storage of labeled lysates as well as the flexibility of derivatizing several different functional groups. After immunoaffinity separation using magnetic microspheres, the protein was electrophoretically separated with the PhastSystem and transferred with the PhastTransfer unit. Using an avidin-linked enzyme amplification system, less than 10 ng of loaded protein could be detected on the transfer membrane. Based on these findings, the PhastTransfer system is a fast, reproducible, and convenient method for the transfer of small quantities of labeled cell surface protein.