    2.3.1.37 | -999 |
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the secondary structure of the enzyme is mostly resilient to pH changes. Partial unfolding is observed at pH 2.0, but further decreasing pH results in acid-induced refolding of the secondary structure to nearly native levels. The tertiary structure rigidity is lost under acidic and specific alkaline conditions, pH 10.5 and pH 9.5 at 37°C, where ALAS populates a molten globule state. As the enzyme becomes less structured with increased alkalinity, the chiral environment of the internal aldimine is also modified. Under acidic conditions, the pyridoxal 5-phosphate cofactor dissociates from the enzyme. Reaction with 8-anilino-1-naphthalenesulfonic acid corroborates increased exposure of hydrophobic clusters in the alkaline and acidic molten globules, far-UV and near-UV circular dichroism study, detailed overview. The alkaline molten globule state of ALAS is catalytically active |
735711 |
