TABLE 1.

Kinetic parameters of S. pneumoniae PBP 2a^*

Protein	Antibiotic			Substrate analogue S2d kcat/Km (M−1 s−1)a	Source or reference
	Cefotaxime k2/K (M−1 s−1)	Benzylpenicillin k2/K (M−1 s−1)	Benzylpenicillin k3 (s−1) [half-life time; h]
PBP 2a*	7,700 (±600)b	<3,800	3.2 × 10−5 [6]	220 (±20)b	This study
PBP 1a*	11,933	34,200	1.0 × 10−5 [14]	256	3
S-PBP 2x*	209,000	99,000	3.5 × 10−5 [5.8]	2,500	18
R-PBP 2x*	3,300	<3,800	4.2 × 10−5 [4.6]	20	18

^aThe k_cat/K_m value of PBP 1a* for S2d reported in this table takes into account the racemic nature of S2d (twofold increase) compared to the value reported in reference 3 

^bThe standard deviation was determined from totally independent measurements.