| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 98 === N-acetyl-D-manosamine, ManNAc, is the precursor for the biosynthesis of sialic acid, NeuAC. To reduce the cost of substrate, an two-enzyme process with N-acetyl-D-glucosamine 2-epimerase, GlcNAc2-epimerase, as the catalyst has been proposed, enabling the use of relatively inexpensive N-acetyl-D-glucosamine, as the starting reactant. Adenosine Triphosphate, ATP, is the activator for GlcNAc 2-epimerase for the alternative process. In this study, we search for the effect of ATP concentration on the activity of the free enzyme and the activity of the enzyme of co-immobilized with ATP. For the free enzyme,the activity will be the maximum as the concentration of ATP in the substrate reaches 1.0mM. For the study of enzyme co-immobilization with ATP, we regard the immobilized enzyme as the control group. The optimal concentration of ATP was 15 mM for the covalent bonding method and 12 mM for the cross-linking method, in these condition the relative activity was 74.2% and 83.3% higher than the control respectively. During the repetitive batch operation, the activity of immobilized enzyme which co-immobilized with ATP appears only at the first batch either covalent bonding or cross-linking method. There is no influence compared with the control after the second batch.
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