Amides, Imides and Peptides

Abstract

IN suggesting the term 'polypeptides' for describing condensates of amino-acids at large, Dr. Jordan Lloyd¹ is seemingly extending the meaning of the word beyond that originally proposed by Emil Fischer², who introduced it for the condensates of α-amino-acids. Indeed, 'peptide' was not proposed for the link –CONH– but for the residue –CHR–CO–NH–, as is indicated by the use of 'dipeptide' for glycylglycine, which contains only one–CONH–group. Fischer, in his original lecture³, put forward the proposal that by analogy with known distinctions made in carbohydrates between disaccharides, trisaccharides, etc., compounds of the glycylglycine type should be termed dipeptides and the higher condensates of amino-acids termed tripeptides, tetrapeptides, etc.