THERMOSTABILITY OF IMMOBILIZED PLANT MICROSOMES

Microsomes from grapewine (V. vinifera L cv. Gamay Freaux) cell homoge nates were immobilized in calcium alginate beads. Cinnamic acid-4-hydr oxylase activities for both freely suspended and immobilized microsome s were compared, resulting in a decrease of 30-40% of the initial acti vity as a consequence of immobilization. This decrease was probably du e to both protein denaturation and microsomal mass losses during the g elation process. Nevertheless, immobilized microsomes showed an enhanc ed thermostability. Only 35% of the initial activity was lost when imm obilized microsomes were incubated at 45-degrees-C for 10 minutes, whe reas a 68% activity loss was observed when dealing with free microsome s.