N

2

ase is made up of two distinct and separately isolated proteins. An Fe protein and an Mo-Fe protein that has two Mo atoms per mole.

99

Mo decays to excited nuclear state of

99

Tc. The angular correlation of the 741—181keV γ rays were emitted subsequently in the deexcitation of the

99

Tc through the medial state 5/2 +.

99

Mo was incorporated in N

2

ase by incubation. After freezing the solution of

99

Mo labelled N

2

ase the attenuation factor G

2

of PAC and quadrapole frequency

ω

e were determind. Compared with the G

2

and

ω

e of other

99

Mo labelled complexes

the oxidation state and coordination structure of

99

Mo in N

2

ase were speculated. The mechanism of nitrogen fixation by N

2

ase was also discussed according to the principle of electron transformation.