Cinnamic carbohydrate esters: new polymeric supports for the immobilization of horseradish peroxidase

Several crosslinking photopolymers were used to cover 3 mm diameter glass beads for immobilising HRP. These immobilization supports were prepared from the totally cinnamoylated derivatives of 4-hydroxybenzaldehyde, glycerine (GLICN), d-sorbitol (SOTCN), d-manitol (MNTCN), 1,2-O-isopropylidene-α-d-glucofuranose (IPGSCN), d-glucuronic acid (GLUCNA), d-gulonic acid (GULCNA), sucrose (SSCN), d-glucosone (GSOCN), d-arabinose (ASCN), d-fructose (FSCN), d-glucose (GSCN), ethyl-d-glucopyranoside (EGSCN), maltose (MSCN), inuline (INCN), dextrine (DXICN), dextrane (DXACN) and polyvinylic alcohol (PVCN). The following partially cinnamoylated derivatives were also used: 2,3,4,6-tetracinnamoyl-d-glucopyranose (GPSTCN), obtained by partial hydrolysis of EGSCN in acid medium, and 3,5,6-tricinnamoyl-d-glucofuranose (GFSTCN), which was obtained by the acid hydrolysis of IPGSCN. The derivatives obtained were cross-linked by irradiation in the ultraviolet region, where these prepolymers show maximum sensitivity. The enzyme was immobilized by adsorption on to the support. The immobilized enzymatic activity varied with the length of incubation (2–21 h) and depended on the chemical nature of the support used. The effect of irradiation time on initial enzymatic activity and on that remaining after storage of the samples with immobilized enzyme was studied; both were seen to be related with the cross-linking density of the final polymer. The immobilized enzyme was more resistant than the soluble enzyme to inactivation by H2O2 at neutral pH, and provided good yields after thermal treatment at this pH value. The results show that the cinnamic esters described are suitable supports for immobilising peroxidase and can be used for different applications of the enzyme on an industrial scale.