Quantum Chemical Study of Penicillin:Reactions After Acylation

摘要

The density functional theory methods were used on the model molecules of penicillin to determine the possible reactions after their acylation on beta-lactamase,and the results were compared with sulbactam we have studied.The results show that,the acylated-enzyme tetrahedral intermediate can evolves with opening of beta-lactam ring as well as the thiazole ring;the thiazole ring-open products may be formed via beta-lactam ring-open product or from tetrahedral intermediate directly.Those products,in imine or enamine form,can tautomerize via hydrogen migration.In virtue of the water-assisted,their energy barriers are obviously reduced.