In enzymology, a putrescine N-hydroxycinnamoyltransferase (EC 2.3.1.138) is an enzyme that catalyzes the chemical reaction

caffeoyl-CoA + putrescine ${\displaystyle \rightleftharpoons }$ CoA + N-caffeoylputrescine

Thus, the two substrates of this enzyme are caffeoyl-CoA and putrescine, whereas its two products are CoA and N-caffeoylputrescine.

This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is caffeoyl-CoA:putrescine N-(3,4-dihydroxycinnamoyl)transferase. Other names in common use include caffeoyl-CoA putrescine N-caffeoyl transferase, PHT, putrescine hydroxycinnamoyl transferase, hydroxycinnamoyl-CoA:putrescine hydroxycinnamoyltransferase, and putrescine hydroxycinnamoyltransferase.

• Negrel J (1989). "The biosynthesis of cinnamoylputrescines in callus-tissue cultures of Nicotiana tabacum". Phytochemistry. 28 (2): 477–481. doi:10.1016/0031-9422(89)80035-4.