An analytical method for the selective retrieval of iminobiotin-derivatized plasma membrane proteins.

An analytical method for the selective retrieval of surface plasma membrane proteins which have been covalently "tagged" with the low-molecular-weight ligand 2-iminobiotin has been developed. Retrieval is based upon the specific interaction between the 2-iminobiotin molecule, avidin, antiavidin antibody, and insoluble protein A from Staphylococcus aureus. Conditions for the reaction include moderately basic pH (8.0-9.0) and moderately high ionic strength (300 mM NaCl). The retrieval reaction is insensitive to 4% (w/v) Triton X-100, NP-40, and Lubrols PX and WX and is inhibited by octyl-beta-D-glucopyranoside and Ammonyx-LO. Large numbers of samples can be processed quickly and simultaneously. Immunoprecipitated proteins can be readily released into solution by incubation in the presence of either low pH, biotin, or sodium dodecyl sulfate.