Phosphinothricin acetyltransferase (, PAT, PPT acetyltransferase, Pt-N-acetyltransferase, ac-Pt) is an enzyme with systematic name acetyl-CoA:phosphinothricin N-acetyltransferase. This enzyme catalyses the following chemical reaction
The substrate phosphinothricin is used as a nonselective herbicide and is a potent inhibitor of EC 6.3.1.2.