| Abstract: | A new route for synthesis of a 32P-labeled Edman reagent 2-(4-isothiocyanatophenoxy)-1,3,2-dioxaphosphinane 2-oxide (PEPITC) is reported. The carrier-free 32P]-PEPITC (specific radioactivity 3.3 X 10(17) Bq/mol) in theory allows the labeling and detection of a minimum amount of 0.1 femtomol of protein. The advantages of the new reagent, which has previously been used for protein sequencing, are demonstrated by gelelectrophoretical and immunological experiments. Its major role is seen in the quantitative monitoring of protein elution from preparative one- and two-dimensional gels. Proteins thus obtained are, after the usual desalting steps, ready for sequencing. |
