Deprotonation of acetone in the alpha-position or deprotonation of the hydroxyl groups in the enol of acetone give one and the same anion: the enolate anion of acetone. You can describe this molecule with two Lewis structures, one that places the negative charge on the O-atom and one that places the negative charge in the C-atom. Take a look at the structure shown and argue which of the Lewis structures is more important.