Kinetic Studies on Gluc-amylase

Publisher Website
Google Scholar
Abstract
The authors consider the kinetics of the mode of action of an enzyme which can act upon 2 different substrates, with special reference to the problem of whether the 2 substrates are acted upon at 1 and the same active center or at 2 separate active centers of the enzyme molecule. The kinetic features which would be expected for single active center mechanism and several types of 2 active centers mechanisms are summarized. Rate of hydrolytic reactions catalyzed by crystalline glucamylase from Rhizopus delemar was studied at 25[degree]C and pH 5.1, using maltose and panose as typical substrates having [alpha]-1,4 and [alpha]-1,6 glucosidic linkage respectively. The apparent Michaelis constant Km and the apparent maximal velocity V were determined for pure and mixed substrates at various mole fractions of maltose. It was found that s/v versus s plot is linear in every case, where v is the initial rate at the total substrate concentration s, and that Km and V vary with the mole fraction of maltose in the manner which is consistent with that predicted by the single active center mechanism. These results have provided strong evidence for a single active center of the enzyme which catalyzes and hydrolyses of both [alpha]-1,4 and [alpha]-1,6 glucosidic linkage of the substrates. A new colorimetric method which is convenient for the determination of glucose in the presence of higher saccharides having reducing power is proposed.

This publication has 1 reference indexed in Scilit: