Table 1.

Kinetic properties and metal contents of purified H. mustelae ureases

Protein	Source	Purification conditions	Vmax [U (mg protein)-1]	Km (mM)	Metals per heterodimer*
UreA2B2	H. mustelae nikR ureB	Aerobic (O2)	NA† (10.7 ± 0.4)	NA†	ICP: 2.3 Fe, 0.2 Zn; PA: 2.01 ± 0.05 Fe
UreA2B2	H. mustelae nikR ureB	EDTA, O2	NA†	NA†	ICP: 2.3 Fe, 0.2 Zn
UreA2B2	H. mustelae nikR ureB	BP‡, O2	NA†	NA†	ICP: 1.9 Fe, 0.1 Zn
UreA2B2	H. mustelae nikR ureB	Anaerobic	14.0 ± 0.2	1.6 ± 0.1	ICP: 1.1 Fe, 0.7 Zn; PA: 1.05 ± 0.07 Fe
UreA2B2	E. coli pEC015	O2	NA†(9.8 ± 0.5)	NA†	ICP: 1.0 Fe, < 0.1 Zn; PA: 1.13 ± 0.12 Fe
UreA2B2	E. coli pEC015	EDTA, βME, O2	NA†	NA†	ICP: 0.8 Fe, < 0.1 Zn; PA: 0.89 ± 0.02 Fe
UreAB	H. mustelae wild-type	EDTA, βME, O2	390 ± 6	1.7 ± 0.1	ICP: 0.6 Ni, 0.2 Fe, < 0.1 Zn
UreAB	H. mustelae nikR ureB2	EDTA, βME, O2	840 ± 20	2.3 ± 0.2	ICP: 1.1 Ni

^*Measured by ICP-AES (ICP) or based on reactivity with 1,10-phenanthroline (PA, average of triplicate experiments ± standard deviation).

^†Not active; numbers in parentheses are specific activities of samples after reductive activation for 80 min.

^‡Treated with 2,2-bipyridyl and dithionite prior to aerobic purification.