Stability and activity of bovine prostaglandin H synthase immobilized on Opuntia imbricata (coyonoxtle)

An immobilization method for prostaglandin H synthase (PGH-synthase, EC 1.14.99.1) from microsomes of bovine vesicular glands on Opuntia imbricata was developed. Study of sorption kinetics showed that the protein sorbed on periodate activated and non-activated support was 45% and 38%, respectively, after 1 h, while after 24 h, it was 68% and 71% of applied protein. The immobilized enzymes retained around 30–40% of initial PGH-synthase activity. The effect of support on enzyme ability to catalyze the synthesis of prostaglandin E2 was observed and compared with cyclooxygenase and cyclooxygenase plus peroxidase reaction, which was detected using electrochemical method and spectrophotometry. Immobilized microsomes were able to catalyze several cycles of arachidonic acid transformation and they were more stable than free enzyme solution upon storage at 4 °C. The activation of the support by means of treatment with periodate showed positive effects on the activity and storage stability of immobilized enzyme. Further, the enzyme immobilization on Opuntia imbricata can be performed by physical adsorption as well as by the chemical attachment on carrier activated by periodate. The differences in the structure of periodate activated and non-activated supports after microsome immobilization were studied using electron microscope.