earticle

영어

Although polymeric supports are being used for enzyme adsorption and immobilization since more than two decades, there is practically no systemic study on the effects of various functional groups present on the polymers on enzyme structure and function. Present work is primarily focused on the effects of functional groups present on copolymers of allyl glycidyl ether and ethylene glycol dimethacrylate (AGE- EGDM) which are functionalized with different groups such as epoxy, hydroxy, tributyamino etc.) on structural integrity and activity of enzymes. The effects of systematic changes in hydrophobicity, polarity, and ionic groups on activity of different classes of enzymes have been studied to understand relative effects of hydrophobic and hydrophilic interactions involved when a protein comes with contact with a polymer. The enzymes chosen for our studies have been selected from different classes: α-chymotrypsin (an
amidase that does not require a co-factor with mol wt of 25 kD), alcohol dehyrogenase (mol wt 144KD) and glucose dehydrogenase (Mol wt 126KD) which need a cofactor NAD(P)H for their reactions, and alkaline phosphatase from shrimp (SAP, mol wt 140KD), a metallo-enzyme in which the metal ion plays a dominant role in reaction. For applications in food and beverage industry, studies have been made with soybean trypsin inhibitor, lipoxidase and pectin methyl esterase. Binding of proteins to the polymers has been studied via adsorption isotherms and activity measurements. Structural changes in the enzymes have been studied by circular dichroism (CD), laser Raman and fluorescence spectroscopy. These studies have shown that hydrophobicity of the polymer plays a dominant role in binding of the protein and polar interactions of the ester groups present in thecopolymer contribute significantly towards protein
denaturation. Use of reverse micellar media overcomes the problem of denaturation and it is possible to obtain immobilized enzyme preparations with significantly improved stability.