The Amino Acid Sequence of Wheat Germ Cytochrome c

Determination of the complete amino acid sequence of wheat germ cytochrome c has shown that the molecule consists of a single polypeptide chain of 112 residues. On alignment with mammalian cytochromes, the peptide chain extends for 8 residues at the NH2-terminal end. In contrast with other cytochromes that have a peptide chain longer than 104 residues, the NH2-terminal residue is N-acetylalanine. Wheat germ cytochrome c contains 8 residues of proline, 4 of which occur in positions not occupied by a proline residue in any of the previously studied cytochromes. Considering only residues 1 through 104, the cytochrome c of wheat germ differs from that of Neurospora crassa in 46 residues, whereas it differs from that of human heart in only 35 residues. For all presently known cytochromes c, the number of amino acid residues which occupy the same position in the sequences is reduced to 35.