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. Author manuscript; available in PMC: 2021 Jun 24.
Published in final edited form as: Chem Rev. 2020 Mar 4;120(12):5107–5157. doi: 10.1021/acs.chemrev.9b00704

Table 5.

Specific Activities for the Reduction of Cyanide and Azide by Nitrogenasea

Product
Protein Substrate H2
(1)h 		N2
(1)		 CH3NH2
(2)		 N2H4
(3)		 CH4
(3)		 NH3
(3)		 ref
Av MoFe KN3 1300 630 53 290b 152
Av VFe KN3 470 51 - 18 - 54b 230
Av MoFe HCNc,f 270 - 29 - 50 50 151
Av MoFe HCNd,f 500e - 70e - 190e 250e 233
Av VFe HCNc,f 560 - 20 - 20 20 230
Av VFe HCNc,g 260 - 27 - 17 22 230
a

The reactions are all reported at 30 °C in an Ar atmosphere with a 20:1 molar ratio of the reductase component to the catalytic component. Units are reported as nmol product × min−1 × (mg protein)−1, converted from nmol of electron pairs × min−1 × (mg protein)−1 from ref 230.

b

there are several potential routes that can generate NH3 from N3−, the activities were converted based on a 6-electron reduction.

c

substrate added as NaCN dissolved in HEPES buffer pH 7.4 with added HCl.

d

substrate added as NaCN dissolved in Tes-KOH buffer, adjusted to pH 7.3 with HCl.

e

reactions reported at pH 7.3 using 8:1 molar ratio of reductase component to catalytic component.

f

5 mM NaCN used.

g

50 mM NaCN used.

h

the number in parenthesis refers to the number of electron pairs required to generate the product.