The role of N-acetylcycloserine in the acyl transfer reactions

The ability of α-N-acetylcycloserine to participate in acyl transfer reactions has been investigated. The reaction with cinnamoylimidazole yields a stable monocinnamoyl intermediate, while that with p-nitrophenyl acetate yields a derivative which undergoes facile deacylation. The kinetics of acylation of α-N-acetylcycloserine and of the deacylation of its acetyl intermediate are reported.

Metal binding tendencies of various antibiotics

A method to determine the presence of metal-drug complexes in dilute solutions is described. Using this method cycloserine was found to complex with cupric, nickelous, zinc and cobalt ions; streptomycin and novobiocin complexed with cupric ions; erythromycin complexed with cobalt ions, and chloramphenicol exhibited no metal binding tendencies. Various penicillins were found to interact with zinc and cupric ions. Preliminary investigations suggest that cupric ions, rather than simply complexing with penicillin as suggested by previous workers, promote the degradation of penicillin to penicilloic acid. Evidence is presented to confirm the presence of penicilloic acid in reaction mixtures initially containing penicillin G or V and cupric ions, and to establish that the reaction follows second order kinetics and ceases when all available cupric ion has been consumed. Good correlation was noted for these results and previous work which showed the effects of metal ions on the antibacterial properties of penicillin.