Kinases
An alcohol attacks ATP’s γ phosphate. The 5’ phosphate goes back on.
You met the other half of this under hydrolysis, and this is not simply the reverse reaction. A phosphatase hydrolyses: water attacks, the bond is destroyed. A kinase transphosphorylates: the five prime hydroxyl attacks the gamma phosphate of ATP and the bond is moved, not made from nothing. Same phosphate, same position on the molecule, opposite directions, and two different mechanisms. That is the clearest case in this lecture that adding and removing are not mirror images. Section divider: Kinases. A hydroxyl attacks the gamma phosphate of ATP, transferring it to the 5-prime end.