The large number of pcptide analogues so far obtained not only include depsipeptides' and hydrazino-peptides.' but also sulphamide' and phosphonic analogucs.' Since all these compounds differ drastically from their pro- totype. their physiological properties are radically changed. It is. however, very likely that the action of N-hydroxypcptides. which are closest to natural amides, will be only slightly modified. The possibility of peptide bond oxidation has not yet ...