Isolation of σ-(L-α-aminoadipyl)-L-cysteinyl-D-valine from culture broths by covalent chromatography

An efficient procedure for the isolation of reduced -(L-α-aminoadipyl)-L-cysteinyl-D-valine (ACV) from culture supernatants of β-lactam antibiotic-producing microorganisms is described. The method utilises covalent chromatography to isolate thiols from culture broths that have been deproteinised and undergone borohydride reduction. 2-Pyridyl disulphide activated thiopropyl Sepharose was employed batchwise to isolate the thiols present in such broths from cultures of the known ACV excreter Cephalosporium acremonium N2 and the penicillin producer Penicillium chrysogenum P2. ACV was separated from these mixtures of thiols by gel permeation chromatograhy. Reversed-phase HPLC analysis showed the ACV to be of a high purity unless isolated from a highly complex culture medium.