抄録
An E. coli mutant (M8328) was isolated by NTG mutagenesis from E. coli KMS3207 which has an inducible N-acetylneuraminate lyase (NPL). The mutant was resistant to catabolite repression and produced NPL constitutively. To improve the productivity of NPL, a hybrid plasmid, pMK6, carrying the npl gene was introduced into the mutant, M8328. The NPL activity level was increased more than 5-fold in the pMK6-harboring mutant compared with that in the mutant, when the cells were grown in inducer (N-acetylneuraminic acid)-free medium. The NPLs produced by the mutant and the pMK6-harboring cells were structurally and immunologically identical with that purified from the parent strain (KMS3207).
