Biosynthesis of the Peptidoglycan of Bacterial Cell Walls

An ATP-dependent phosphokinase which catalyzes the conversion of C55-isoprenoid alcohols and some other related substrates to the C55-isoprenoid alcohol phosphates is present in the membrane fraction of Staphylococcus aureus. The product of the reaction is a substrate for the synthesis of lipid intermediates in peptidoglycan synthesis. The enzyme has the unusual property of being extracted into acidic butanol-1 at room temperature and can then be further purified by precipitation from butanol at -15°. The material so obtained is soluble in a number of organic solvents in addition to butanol-1 and exhibits a relatively high degree of stability in these solvents. It is insoluble in water and relatively unstable on suspension in this solvent. The presence of this enzyme and of C55-isoprenoid alcohol in S. aureus accounts for the stimulation by ATP of peptidoglycan synthesis catalyzed by particulate enzyme from this organism. A possible function for the enzyme is discussed.