Involved in the synthesis of hordatines (antifungal hydroxycinnamoylagmatine derivatives). Specific for agmatine as the acyl acceptor, inactive towards tyramine and putrescine. Has activity with the acyl donors 4-coumaroyl-CoA, cinnamoyl-CoA, caffeoyl-CoA, feruloyl-CoA, and to a lesser extent sinapoyl-CoA. 4-coumaroyl-CoA + agmatine = CoA + H(+) + N-(4-guanidinobutyl)-4-hydroxycinnamamide Optimum pH is 7.5. Monomer. Belongs to the plant acyltransferase family.