S-AI catalyzes the irreversible decomposition of sucrose into fructose and glucose at pH 4.5 to 5.0 (acidic).
It is one of the key enzymes for sucrose metabolism in soil microorganisms.
S-AI catalyzes the degradation of sucrose to produce reducing sugar, and further reacts with 3,5-
dinitrosalicylic acid to form brownish red amino compound, which has characteristic light absorption at
540 nm, and the increase rate of light absorption at 540 nm in a certain range is in direct proportion to NI
activity. The activity of S-NI is calculated by the increasing rate of light absorption.
Reagents and Equipment Required but Not Provided
Spectrophotometer, centrifuge, water-bath, transferpettor, 1 mL glass cuvette, mortar/ homogenizer,
toluene, sieve (50 mesh, or smaller) and distilled water.