The Structure of a Chymotryptic Peptide from Pseudomonas Cytochrome C-551.

A micromethod involving the use of fluorescent derivatives of 1-dimethylaminonaphthalene-5-sulphonyl chloride (Gray & Hartley, 1963) has been used in a parallel study of the structure of peptide C8Pla (as defined by Ambler, 1963) of the Pseudomonas cytochrome c-551. The basis of the method was a modification of the phenyl isothiocyanate procedure for the removal of the N-terminal residue (Edman, 1950 a, b), followed by investigation of the free amino groups of the residual peptide The very high sensitivity of the fluorescent end-group reagent used enabled the subtractive procedure to be applied over six consecutive steps, commencing with approx. 0-02 timole of peptide. The partial sequence