CYCLIZATION OF o-(L-(C-AMINOADIPYL)-L-CYSTEINYL-D-VALINE TO PENICILLINS BY CELL-FREE EXTRACTS OF STREPTOMYCES CLAVULIGERUS
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چکیده
Cell-free extracts prepared by sonication of Streptomyces clavuligerus cyclized 6-(L-aaminoadipyl)-L-cysteinyl-D-valine (ACV) into a penicillin-type antibiotic. The antibacterial spectrum of this antibiotic suggested it was a mixture of isopenicillin N and penicillin N indicating that both cyclization and racemase activities were present. Cyclization activity was optimal in extracts prepared from 48 hours cultures. Extracts incubated at 20°C produced antibiotic for 2 hours before activity ceased. Cyclization activity showed an absolute requirement for dithiothreitol (DTT) and 02 and was stimulated by ascorbic acid and FeSO4. No requirement for ATP was observed.
منابع مشابه
Production of the penicillin precursor 5-(L-a-aminoadipyl)-L-cysteinyl-D-valine (ACV) by cell-free extracts from Streptomyces clavuligerus
Glycerol-stabilised cell extracts of Streptomyces clavuligerus contain an enzyme activity which synthesises ACV from the individual amino acids L-a-aminoadipic acid, t-cysteine and L-valine. Enzyme activity was optimum in reaction mixtures containing 1 mM ATP together with an ATP regenerating system. The ACV synthetase enzyme formed ACV analogs when provided with Lcarboxymethylcysteine in place...
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