Peptide antibiotic AS-48 exerts a bactericidal mode of action on exponential cultures of Escherichia coli K-12 through a multi-hit kinetics interaction. AS-48 causes a parallel and gradual cessation of all biosynthetic pathways monitored (protein, RNA, DNA, and cell wall synthesis), the rate of incorporation of labeled precursors, the rate of O2 consumption, and cell growth. These effects have been attributed to alterations of cytoplasmic membrane functions.