p-Nitrophenetole deethylase activity of rat liver microsomes entrapped in polyelectrolyte capsules

Liver microsomes from phenobarbital induced rats are entrapped in capsules prepared from polyelectrolytes. A comparative analysis of the deethylase activity against p-nitrophenetole by encapsulated and freely suspended microsomes is carried out. The pH optimum occurs at about 7.2 for encapsulated as well as free microsomes. The pH activity profile of encapsulated microsomes, however, is strongly flattened. The maximal velocity of entrapped microsomes is about a quarter of that of free microsomes. The Michaelis-Menten constants are virtually equal. Despite of the lowered activity of encapsulated microsomes this kind of immobilization of enzymes may be useful in biotechnology and medicine because mild immobilization conditions like room temperatures and aqueous solutions are realized.