Figure 1

General pathway of arginine biosynthesis in prokaryotes including two known routes for removal of the acetyl group. Vertical arrows represent the linear pathway, whereas the alternative cyclic pathway in which the acetyl group is recycled by ornithine acetyltransferase (encoded by argJ) is indicated by a dashed arrow. Intermediates and immediate precursors are given in bold letters, enzymes are in boxes. ArgJ* designates bifunctional proteins. Abbreviations: HS-CoA = coenzyme A; Ac-CoA = acetyl-CoA; (P)P_i = (pyro)phosphate; HCO₃- = bicarbonate.