The Collaborative International Dictionary of English v.0.48:

Transact \Trans*act"\, v. t. [imp. & p. p. Transacted; p. pr.
   & vb. n. Transacting.] [L. transactus, p. p. of transigere.
   See Transaction.]
   To carry through; to do; perform; to manage; as, to transact
   commercial business; to transact business by an agent.
   [1913 Webster]