TABLE 2.

Relative efficiencies of MurDs from various bacterial species

Origin	Form of MurD	Vmax (nmol/min · mg)a	Km(app) (μM)a			Vmax/Km(app, UDPNacMur-l-Ala)	Relative efficiency
			UDPNacMur-l-Alab	ATP	d-Glutamatec
S. aureus	MBP-MurD fusion protein	31,787 ± 3,668	245 ± 29	78 ± 9	660 ± 51	12,974	0.14
	Regenerated MurD	32,118 ± 3,636	290 ± 34	84 ± 10	534 ± 25	11,075	0.12
E. faecalis	MBP-MurD fusion protein	32,857 ± 3,647	38 ± 4	44 ± 5	121 ± 10	86,466	0.90
	Regenerated MurD	29,823 ± 5,934	36 ± 7	47 ± 4	118 ± 14	82,842	0.87
E. coli	MBP-MurD fusion protein	5,965 ± 297	5 ± 2	154 ± 23	27 ± 12	85,214	0.89
	Regenerated MurD	4,783 ± 423	7 ± 3	135 ± 33	42 ± 11	95,660	1.00
H. influenzae	MBP-MurD fusion protein	NDd	ND	ND	ND	ND	ND
	Regenerated MurD	13,111 ± 2,199	8 ± 4	102 ± 6	169 ± 20	163,888	1.71

^aGram-positive MurD activity was determined with the coupled PK-LDH assay (up to 10 min). 

Gram-negative MurD (1- to 2-min assay) was assayed by HPLC or coupled enzyme assay. 

All assays were done in duplicate, and a minimal of three independent experiments were conducted for each kinetic determination. 

Reaction rates within the linear region of product formation were used for parameter analysis. 

^b0 to 2 mM UDP-N-acetylmuramyl-l-alanine (UDPNacMur-l-Ala) was used for gram-positive MurD assay; 0 to 200 μM was used for gram-negative MurD assay. 

^cThe ranges of ATP and d-glutamate used in gram-negative MurD assays were from 0 to 1 mM and from 0 to 2 mM, respectively. 

The ranges of ATP and d-glutamate used in gram-positive MurD assays were from 0 to 1 mM and from 0 to 5 mM, respectively. 

^dND, not determined.