Abstract:
Millet seedlings (Ex-Borno, Gero type) were grown and crude cell
extract of the leaves was used to assay for the activity of Nitrate
reduCtase (EC 1.6.6.1) spectrophotometrically at 540 nm according
to Neyra and Hageman method (1975). Michealis-menten constant,
km, and maximum velocity, Vmax, were found to be 106.55 pM and
15.18 umote min" gram·' tissue respectively. Optimum temperature
was found to be 35 DC,while optimum pH was 6.5. The activation
energy ot the reaction was 38.29 KJ mote", Glutathione was found
to inhibit the enzyme competatively with ki of 2.33 x to: pM.
Residual activity rate constant at 30°C, 40°C and 50°C were 3x1~
min", 6 x 10-3 min" and 9 x 10-3 min" and the biological half life of
the corresponding temperatures were 231.0 , 115.5 and 77.0
minutes respectively. Activation energy between 30°C and 40 °C
was 25.027 KJ mot' and for40DC and 50DC it was 292.805 J mot',
The enthalpy of ectivetion, H* was 22.508 KJ mot' K' and enthropy
S· was -218.27 Jmot' 1\'. The free energy ~as 88.642 KJ mot' K'.
