Via the Tat-dependent transport pathway folded proteins are translocated over the thylakoid membrane. The translocase consists of three integral membrane proteins, TatA, TatB and TatC. For binding of the precursor protein TatB and TatC form a receptor complex. TatA mediates the transport over the thylakoid membrane via a so far unknown mechanism. The aim of this work was the establishment and characterization of spinach as an alternative model system for cpTat-dependent transport. In addition to the high variability of the transport rates in serveral experimental runs, a stronger extraction for spinach TatA from the thylakoid membrane was observed during the washing steps. In addition, the TatA protein from spinach was tested for its activity. With the help of concentration-dependent transport reconstitution experiments, this could be determined and compared with the activity values of pea and Arabidopsis TatA. There were differences in activity which, according to further investigations, are caused by sequence differences in the C-terminus of TatA.