1,2-Diaminoethane and diaminomethane were coupled to aspartic acid residues in small peptides by means of a water-soluble carbodiimide. The resulting modified side chains sufficiently resembled lysine for trypsin to cleave the peptides. Similar modification of glutamic acid residues in peptides gave little or no susceptibility to trypsin.

The sequences of a thirteen residue glycopeptide containing the sole cysteine residue of stellacyanin and a pentapeptide containing histidine were determined by the dansyl-Edman method. There is relatively little homology between stellacyanin and plastocyanin or azurin in the cys region and the adjacent histidine proposed as a ligand to Cu in plastocyanin and azurin is absent in stellacyanin. There are homologies between the Cu subunit of cytochrome oxidase and these “blue” copper proteins, in this region. The his peptide shows homologies with the sequence around an invariant his in plastocyanin.