Table 1.

Kinetic properties and metal contents of purified H. mustelae ureases

ProteinSourcePurification conditionsVmax [U (mg protein)-1]Km (mM)Metals per heterodimer*
UreA2B2H. mustelae nikR ureBAerobic (O2)NA (10.7 ± 0.4)NAICP: 2.3 Fe, 0.2 Zn; PA: 2.01 ± 0.05 Fe
UreA2B2H. mustelae nikR ureBEDTA, O2NANAICP: 2.3 Fe, 0.2 Zn
UreA2B2H. mustelae nikR ureBBP, O2NANAICP: 1.9 Fe, 0.1 Zn
UreA2B2H. mustelae nikR ureBAnaerobic14.0 ± 0.21.6 ± 0.1ICP: 1.1 Fe, 0.7 Zn; PA: 1.05 ± 0.07 Fe
UreA2B2E. coli pEC015O2NA(9.8 ± 0.5)NAICP: 1.0 Fe, < 0.1 Zn; PA: 1.13 ± 0.12 Fe
UreA2B2E. coli pEC015EDTA, βME, O2NANAICP: 0.8 Fe, < 0.1 Zn; PA: 0.89 ± 0.02 Fe
UreABH. mustelae wild-typeEDTA, βME, O2390 ± 61.7 ± 0.1ICP: 0.6 Ni, 0.2 Fe, < 0.1 Zn
UreABH. mustelae nikR ureB2EDTA, βME, O2840 ± 202.3 ± 0.2ICP: 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.