Preparation and Characterization of Taka-amylase A Attached to Carboxymethyl Dextran by Water-soluble Carbodiimide(Biological Chemistry)

概要

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For the cross-linking of Taka-amylase A (TAA) to carboxymethyl dextran (CM-Dex), the use of water-soluble carbodiimide (EDC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) was examined. CM-Dex was treated with EDC and the carboxyl groups were converted into the activated form, and then, the activated CM-Dex was attached to TAA. Purification of the modified TAA was done by a column of DEAE-Sephacel, where 80% of the enzyme activity was eluted at the breakthrough fraction (M-TAA I). About 14% of the activity was eluted with 0.25MNaCl (M-TAA II). Polyacrylamide gel electrophoresis showed an increase in the carbohydrate at the position of native TAA. The Km values of M-TAA I and II for the soluble starch were 2〜6-fold higher than that of native TAA, while Km values for γ-cyclodextrin were at the same level as the native TAA. Although the pH stability of M-TAA I at the acidic limb of pH 3.0〜4.5 decreased slightly, the stability at the alkaline limb of pH 10.0〜11.0 was improved. There were some increase in the stability against the denaturation by methanol.
社団法人日本農芸化学会の論文
1989-12-23