ABSTRACT
<p><b>OBJECTIVE</b>To provide materials for the study of the function of ESC42 protein specifically expressed in the human epididymis.</p><p><b>METHODS</b>The ESC42 gene was amplified from the human epididymis cDNA library by PCR and then cloned into prokaryotic expression vector pGEX-4T-1, expressed and purified by recombinant DNA techniques. The specificity of ESC42 protein was identified by Western blot and MALDI-TOF-MS. The database was searched by Ms-Fit.</p><p><b>RESULTS</b>The recombinant plasmid expressed a Mr 38 x 10(3) fusion protein in E. coli at a level of 30% of the total protein, and the purity was as high as 99%. The ESC42 protein was identified by ESC42 monoclonal antibody and its molecular weight was 11 978.12, tested by MALDI-TOF-MS. The peptide mass fingerprint analysis showed that the coverage rate of the sequence reached 48% with 100% matching. The motif scan in Prosite database reveal that ESC42 belonged to the beta-defensin family and had antibacterial activity.</p><p><b>CONCLUSION</b>Obtaining high purity of rhESC42 protein may lay a foundation for the study of its functions.</p>