RESUMO
<p><b>OBJECTIVE</b>To study the inhibition activity of Semenogelin (Sg) and its different peptides to human spermatozoa.</p><p><b>METHODS</b>Human Sg DNA and its N-terminal Sg and C-terminal Sg DNA were cloned into PET-100 vector. Positive colonies were screened and transformed into E. Coli BL21 (DE3). Recombinant Sg and its peptides were induced and expressed in high competent E. coli BL21 (DE3) , and purified by 50% Ni-NTA column. Inhibition activity assay was done by adding 4 different concentrations of semenogelin and its two peptides, 0, 1, 5 and 10 ng/microl, to human spermatozoa.</p><p><b>RESULTS</b>The peptide of Semenogelin that inhibits the activity of human spermatozoa was located in its N-terminal fragment. C-terminal Sg did not inhibit the activity of spermatozoa.</p><p><b>CONCLUSION</b>N-terminal Sg is the inhibition peptide of the whole molecular Sg. During semen liquefaction, this peptide should be cut off from the surface of human spermatozoa before they move forward.</p>