The peptidoglycan of Escherichia coli K-12 strain AB264 was isolated by treating whole cells with sodium dodecyl sulfate and was purified by deoxyribonuclease, ribonuclease, and trypsin treatment. Like the peptidoglycan of Bacillus subtilis, this peptidoglycan proved able to bind substantial amounts of metallic ions from aqueous solution. In particular, most metals of the transition I series were bound from solution in amounts greater than or equal to 1 mumol/mg dry weight peptidoglycan.