Large-scale purification and characterization of recombinant tick anticoagulant peptide

Recombinant tick anticoagulant peptide (r-TAP), a potent and specific inhibitor of blood coagulation factor Xa, was purified to > 99% homogeneity at the multi-gram scale. Genetically engineered yeast secreted 200–250 mg/l of the heterologous protein into the medium. Cells were separated from broth by diafiltration and purification was done by two chromatographic steps, both conducive to operation on a large scale. Analysis of the purified protein by several methods indicated that it was > 99% homogeneous and no incompletely processed or truncated proteins were detected. Physico-chemical characterization data of r-TAP show that it exists as a monomer in solution and no evidence of post-translational modification was observed. The purified protein was fully active in inhibiting human coagulation factor Xa.