Abstract: INDIRECT IODIZATION LABELLING OF CAMODULINZhang Zhongshu Xu Ruiji Wang Guohong Zhao Jiwen Shi Yiqun(Department of Nuclear Medicine,Nanjing General Hospital of PLA,Nanjing 210002)ABSTRACTThe iodinated calmodulin with 125I by the indirect iodination method is prepared.The specific radioactivity of 125ICaM is 1.56 MBq/μg，the total labelling rate of 125I is 23.1%. Clinical tests indicate that the specificity,stability and other technical specifications of the iodinated CaM can satisfy the needs of RIA for reducing the harm of direct iodination to the antigen.Key words Calmodulin 125I Indirect labelling