An in situ method to study the reaction catalyzed by alkaline phosphatase on DNP

The reaction catalyzed by alkaline phosphatase on disodium-pnitrophenyl phosphate was studied in a reaction media composed of sucrose (43.5 and 53.5%, w/w) and sucrose (43.5%, w/w) + polysaccharide (10%, w/w) added with agar-agar (0.5%, w/w) at low temperatures (20, 0 and -5C). The results show that temperature and concentration of sucrose and sucrose + dextran in the media affect the enzymatic reaction. The presence of 10% dextran (molecular weight of 104 g/mol, w/w) in the reaction medium decreased the reaction rate. This could be explained by the increase in the viscosity of the medium, due to the presence of this polysaccharide. The experimental data were compared with predicted values, calculated from Atkins theory. The results show that in our experimental conditions described previously, the reaction catalyzed by alkaline phosphatase cannot be predicted by Atkins theory, probably because the viscosity was not the main parameter governing the reaction.