The Immobilization Of Human Arginase ? And Its Application To Produce L-ornithine

To our knowledge,L-ornithine(L-Orn),which presents in various kinds of cells and tissues,is intermediate product of urea precursors and plays very important roles in organism metabolism.It contributes to detoxification of excess ammonia collection in our body.And it also can strengthen the immune system,protect liver,wipe off surplus fat and so on.It plays an irreplaceable role in the health care and medical industry.Arginase usually exists in the body of animals who produce urea,which has a catalytic formation of L-Orn.Enzyme immobilization technology is to use solid materials binding or restricting enzymes in certain areas.And enzymes still have its unique catalytic reaction,and can be recycled and reused.After immobilization,it has the merits of improvement of stability,easy to separate from reaction system,easy transportation and storage and is also conducive to automated production.Therefore,immobilized enzyme has a very attractive prospect in the industrial production,chemical analysis,medicine and so on.In this study,arginase are obtained from human arginase I(ARG I)yeast recombinant strains,which has been screened and conserved by our laboratory.We use chitosan as the carrier,glutaraldehyde as crosslinking agent to prepare immobilized ARG I.The results indicate that free ARG I and immobilized ARG I both exhibit the optimal activity under the same condition of pH 10 at 40?.However,the immobilized one present not only the remarkable thermal and long-term stability but broad adaptability to pH,suggesting its potential to be widely applied in future industry.After careful analysis of its catalytic conditions,the immobilized ARG I has been employed to catalyze the conversion of L-arginine(L-Arg)to L-Orn under an optimal condition of 1%glutaraldehyde,1 mM Mn2+,40 ?,pH 10 and L-Arg concentration of 200 g/L,achieving a highly converted content of 149.2 g/L L-Orn and a transformation rate of 98%.