Figure 4.

Identification of the Pro⁶² Pro-IR processing site by radio sequencing. HEK293 cells expressing Pro⁶² receptors were metabolically labeled, then immunoprecipitated and processed for gel electrophoresis. cpms in the eluted fractions are shown, and each point represents the mean from at least three separate experiments expressed as the fold-increase over baseline. The receptor sequence is shown below in single-letter amino acid codes. (A) Radio sequencing of the 120-kDa protein and (B) the 80-kDa protein.