Soil Neutral Invertase (S-NI) Activity Assay

S-NI catalyzes the irreversible decomposition of sucrose into fructose and glucose under neutral conditions and is one of the key enzymes in the sucrose metabolism of soil microorganisms. S-NI catalyzes the degradation of sucrose to produce reducing sugars, which further react with 3,5-dinitrosalicylic acid to produce brown-red amino compounds, which are characteristic at 540nm.

Light absorption, within a certain range, increases the rate at 540nm which is directly proportional to NI activity.