Boronic acid transition state inhibitors (BATSIs) with R1 side chains of cefotaxime and ceftazidime were assayed against SRV-1, SHV-2, SHV-5, D104K, and D104K G238S beta-lactamases. The D104K variant was the most susceptible to inhibition by the ceftazidime BATSI (K-i, 730 +/- 80 nM), while the D104K G238S variant was the most susceptible to the cefotaxime BATSI (K-i, 1.1 +/- 0.2 mu M)
