2.7.1.173	native enzyme partially by ammonium sulfate fractionation	
2.7.1.173	recombinant His-tagged NRK1 from Escherichia coli strain BL21(DE3) by nickel affinity chromatography and gel filtration	
2.7.1.173	recombinant Nrk1 and Nrk2 from Escherichia coli by metal chelate affinity chromatography	
2.7.1.173	recombinant Nrk2 from Escherichia coli by metal chelate affinity chromatography