Abstract
O-Diazoacetyl-L-serine (azaserine) inhibited the multiplication of Gaffkya homari equally well in the presence of exogenous purines as when purines were synthesized endogenously (in p-aminobenzoic acid-containing media). Purine synthesis is not the main site of inhibition by azaserine in this microorganism. Glutamine, arginine, and glutamic acid annulled the inhibition by azaserine. The role of azaserine in N transfer is discussed.