Abstract
Iodination of E. coli cells with chloramine T preferentially labels the free and murein-bound forms of the outer membrane lipoprotein. Iodination for 15 s at 15.degree. C labels the 2 forms of the lipoprotein almost exclusively, but iodination for 60 s at 25.degree. C also labels the other major outer membrane proteins. Chloramine T iodination is a rapid, simple technique for [radio-]labeling the outer membrane lipoprotein.