Effects of pH on the Aggregation of Choline-treated E-Amidase of Streptococcus pneumoniae(Biological Chemistry)

概要

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Pneumococcal E-amidase (36.5 kDa, inactive form of the amidase) incubated with choline aggregates to form a high molecular mass (> 500 kDa), active C-amidase upon the removal of choline by dialysis at neutral pH. When choline was removed at alkaline pH (pH 8-9), aggregation of the enzyme was severely inhibited. The non-aggregated enzyme obtained at alkaline pH easily aggregated in the absence of choline and was active when the pH was shifted to neutral (pH 7). Furthermore, the high molecular mass amidase formed at neutral pH was dissociated at pH 9 to a low molecular mass (about 36.5 kDa). The dissociated amidase also reaggregated and was active when it was simply exposed to neutral pH. Since the original E-amidase itself neither aggregated nor was active by such a pH shift, these amidases obtained after the removal of choline at alkaline pH were suggested to be the intermediate molecules of the choline-mediated conversion of inactive E-amidase to the active form.
社団法人日本農芸化学会の論文
1991-04-23