a Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina
b Departamento de Química Biológica, Facultad de Ciencias Químicas, Uniuersidad National de Córdoba, 5016-, Córdoba, Argentina
Abstract:
Phospholipase A2 selectively hydrolyses the ester linkage at the sn-2 position of phospholipids forming lysocompounds. This bioconversion has importance in biotechnology since lysophospholipids are strong bioemulsifiers. The aim of the present work was to study the kinetic behaviour and properties of immobilized phospholipase A2 from bee venom adsorbed into an ion exchange support. The enzyme had high affinity for CM-Sephadex® support and the non-covalent interaction was optimum at pH 8. The activity of immobilized phospholipase A2 was comparatively evaluated with the soluble enzyme using a phospholipid/Triton X-100 mixed micelle as assay system. The immobilized enzyme showed high retention activity and excellent stability under storage. The activity of the immobilized system remained almost constant after several cycles of hydrolysis. Immobilized phospholipase A2 was less sensitive to pH changes compared to soluble form. The kinetic parameters obtained (Vmax 883.4 μmol mg−1 min−1 and a Km 12.9 mM for soluble form and Vmax = 306 μmol mg−1 min−1 and a Km = 3.9 for immobilized phospholipase A2) were in agreement with the immobilization effect. The results obtained with CM-Sephadex®-phospholipase A2 system give a good framework for the development of a continuous phospholipid bioconversion process.