The amino acid sequence of the plastocyanin from French bean (Phaseolus vulgaris) was determined. The protein consists of a single polypeptide chain of 99 residues, and the sequence was determined by characterization of CNBr, tryptic, chymotryptic and thermolysin peptides. When the sequence is compared with that from the plastocyanin of the unicellular green alga Chlorella fusca, the French-bean protein shows the deletion of the N-terminal residue, a two residue insertion and 53 identical residues. Detailed evidence for the sequence of the protein has been deposited as Supplementary Publication SUP 50037 (16pp., 1 microfiche) at the British Library (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.
