Invertase (Ivr) catalyzes the irreversible decomposition of sucrose into fructose and glucose, which is one
of the key enzymes in sucrose metabolism of higher plants. According to the optimal pH, Ivr can be
divided into acid invertase (AI) and neutral invertase (NI). NI mainly exists in the cytoplasm and is
responsible for decomposing sucrose into fructose and glucose.
NI 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 a 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 NI is calculated by the increasing rate of light absorption.
Reagents and Equipment Required but Not Provided
Spectrophotometer/microplate reader, desktop centrifuge, water-bath, adjustable pipette, micro glass
cuvette/ 96 well flat-bottom plate, mortar/homogenizer, ice and distilled water.
