Mechanism
Recently, the roles of active site residues in human galactokinase have become understood. Asp-186 abstracts a proton from C1-OH of α-D-galactose, and the resulting alkoxide nucleophile attacks the γ-phosphorus of ATP. A phosphate group is transferred to the sugar, and Asp-186 may be deprotonated by water. Nearby Arg-37 stabilizes Asp-186 in its anionic form and has also been proven to be essential to galactokinase function in point mutation experiments. Both the aspartic acid and arginine active site residues are highly conserved among galactokinases.
Read more about this topic: Galactokinase
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