“…Naked sacculi prepared from E. coli cells proved to be the most suitable material for getting a sufficiently clear picture from such investigations, since lysozymes can break them down completely into small fragments. Under suitable conditions, E. coli murein yields essentially two types of fragments, or muropeptides according to our terminology, in molar proportions of about 1 : 1 (14,56). The structural formula of the smaller one, briefly designated C6, is shown in Figure 3 (12,13).…”