Use of Iodo-Gen and Iodine-125 to label the outer membrane proteins of whole cells of Neisseria gonorrhoeae

The outer membrane proteins of Neisseria gonorrhoeae are specifically labeled by use of 1,3,4,6-tetrachloro-3α,6α-diphenyl glycoluril (Iodo-Gen) and ¹²⁵I under the conditions described in this report. Use of this procedure with whole cells of N. gonorrhoeae produces a clear labeling pattern which can be visualized by electrophoretic separation of the proteins, followed by autoradiography. Electrophoretograms reveal some 70 polypeptide bands, while autoradiograms reveal only 5 or 6 labeled bands. The labeled polypeptide bands correspond to isolated outer membrane proteins, the most intensely labeled of which is the principal outer membrane protein. The method described in this report is both specific and gentle, as well as rapid and convenient.