The present invention is directed to an anti-tumor protein coupled with a specific modifiying reagent at a specific site to overcome the inherent deficiencies of the anti-tumor protein, such as a high antigenicity and a short half-time, and to overcome the deficiencies resulted from a non-specifically modifying method, such as inconsistent modified sites, inhomogeneous constitutes, significantly decreased activity and hard-to-control quality of the products, and to ultimately make it available for the treatment of tumors and production of anti-tumor medicaments.
