Replacement of the 3-carboxylate residue in phenoxymethylpenicillin by an aldehyde group gives a good substrate for E. cloacae P99 βlactamase with, kcat = 34 s-1, Km = 7.5 × 10-5 mol dm-3 and kcat/Km = 4.5 × 10 5 dm3 mol-1 s-1 at pH 7. With B. cereus 569/H β-lactamase I as a catalyst, kcat/Km = 1.87 × 104 dm3 mol-1 s-1 at pH 7 and shows a bell-shaped dependence on pH with apparent pKas of 4.76 and 9.72. Any close proximity between the penicillin 3-aldehyde and a lysine amino group on the protein does not result in iminine formation and inhibition of the enzyme.
|Number of pages||2|
|Journal||Journal of the Chemical Society, Perkin Transactions 2|
|Publication status||Published - 1 Dec 1995|