Abstract: STUDY ON THE LABELING OF DTPAPROTEIN　WITH153SmChen Lai Bao Borong(School of Chemistry and Chemical Engineering, Shanghai University,201800)Zhuang Daoling Zhou Zhentang(Shanghai Institute of Nuclear Research, 201800)Li Guiping Fong Guowei Li Biao Shi Ailan Zhu Chengmo(Ruijin Hospital,Shanghai 200025)ABSTRACTThe conjugating reaction of CADTPA with BSA、 SA、 CEAMAb and IgG is studied, the labeling method of proton with 153Sm is established,and the better conditions are selected. The biological activity of some conjugates is detected, and the serum stability of 153SmDTPAIgG is examined. Experimental results indicate the retained bioreactivity of DTPASA with biotin is 56.5%, and the immunoreactivity of DTPAMAb is the same as PAb. The MAb labeled with 153Sm has a specific activity of 2.35 GBq/g. 153SmDTPAIgG is very stable in mice serum, without releasing free 153Sm within 41 hours.Key words labeling of 153Sm CADTPA BSA CEAMAb IgG conjugating reaction bioreactivity immunoreactivity