Objective To try making huZP3a22-176 and huZP3b177-348 polypeptides (representing anintact huZP322-348 protein without its N-terminal signal peptide and C-terminal trans-membrane domain ) express in E. coli at a higher levelMethods The cDNAs encoding huZP3a and huZP3b were obtained with PCR method.The pBV221 plasmid was used to construct thermo-inducible recombinant expressionvector. Purification of two target expression products employed an improved methodof preparative gel polyacrylamide gel electrophoresis.Results Two polypeptides of recombinant huZP3a (rhuZP3a) and recombinant huZP3b(rhuZP3b) were all expressed respectively in an E. coli BL21(DE3)pLysS strain at ahigher level, which were recognized by two specific polyclonal antisera in Westernblotting test which recognize a linear B cell epitope present in rhuZP3a or rhuZP3brespectively. Using the shake-flask method, approximately 5 mg of rhuZP3a and rhuZP3bwith more than 95% relative homogeneity were harvested from 1 L culture respectively.Conclusion The availability of two rhuZP3 polypeptides will help in detecting theimmunogenicities of rhuZP3a and rhuZP3b through animal experiments andconfirming the function domain of non-glycosylated huZP3 to induce acrosomereaction in vitro. Objective To try making huZP3a22-176 and huZP3b177-348 polypeptides (representing anintact huZP322-348 protein without its N-terminal signal peptide and C-terminal trans-membrane domain) express in E. coli at a higher level Methods The cDNAs encoding huZP3a and huZP3b were obtained with PCR method. The pBV221 plasmid was used to construct thermo-inducible recombinant expression vector. Purification of two target expression products employed an improved method of preparative gel polyacrylamide gel electrophoresis. Results Two polypeptides of recombinant huZP3a (rhuZP3a) and recombinant huZP3b (rhuZP3b) were all expressed respectively in an E. coli BL21 (DE3) pLysS strain at ahigher level, which were recognized by two specific polyclonal antisera in Western blotting test which recognize a linear B cell epitope present in rhuZP3a or rhuZP3 precisely identified. Using the shake-flask method, approximately 5 mg of rhuZP3a and rhuZP3b with more than 95% relative homogeneity were harvested from 1 L culture re spectively. Confluence The availability of two rhuZP3 polypeptides will help in detecting the immunogenicities of rhuZP3a and rhuZP3b through animal experiments andconfirming the function domain of non-glycosylated huZP3 to induce acrosome reactions in vitro.