AIM:To understand the interaction between a195- kilodalton protein,P195, on the surface of Plasmodium falciparum merozoite and human erythrocyte.METHODS:P195 was expressed in eight fragments in E.coli.After being refolded,the expressed proteins were la- belled with12 5 I,and incubated with human erythrocytes.RESULTS:According to binding assay, three fragments of P195:M3,M6,M9were found to have ability to bind to human erythrocyte. M6,which is equal to amino acid( AA) sequence from384 to595,could bind to human erythro- cytes but not to trypsin treated human erythrocytes,and the binding could be eluted by low p H buffer solution. M3( AA 12 3to 30 2 ) and M9( AA 10 78to 12 51) also have the ability to bind to human erythrocytes,but the binding was not affected by trypsin treatment and low p H buffer elu- tion. CONCL USION:The binding site of M6might be a surface protein receptor of human ery- throcytes,while the binding site of M3and M9might be an intracellular componentof human ery- throcyte.