[Correlation of epididymal protease inhibitor Eppin and Semenogelin on human ejaculated spermatozoa].
OBJECTIVE
To evaluate the correlation of epididymal protease inhibitor(Eppin) and Semenogelin(Sg) on human ejaculated spermatozoa.


METHODS
The experimental approaches include: (1) Immunoprecipitation of Eppin with anti-Eppin from semen; (2) Colocalization of Eppin and Sg by immunofluorescence; (3) Immunoprecipitation of rEppin and rSg;(4) Far-Western blotting of rEppin and rSg;(5) Competition of saturated 125I-rSg binding to rEppin with unlabeled Sg, and direct binding of 125I-rSg to rEppin on a blot; (6) Autoradiography of 125I-rSg with rEppin.


RESULTS
Eppin-Sg complex present on the surface of human ejaculated spermatozoa, Cys-239 is the only cystein for rEppin binding rSg. Reduction and carboxymethylation of Cys-239 blocks binding of 125I-rEppin to rSg.


CONCLUSIONS
Our study demonstrates that Eppin and Sg bind to each other on human ejaculated spermatozoa. A disulfide linkage occurs between Sg and Eppin, indicating the specificity of binding.
Wang
Zeng-Jun
ZJ
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
Wu
Hong-Fei
HF
Qian
Li-Xin
LX
Qiao
Di
D
Shao
Jian-Feng
JF
Zhang
Wei
W
Sui
Yuan-Geng
YG
Xu
Zheng-Quan
ZQ
D006801:Humans; D008297:Male; D011485:Protein Binding; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins; D029607:Seminal Vesicle Secretory Proteins / Q000737:chemistry / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism*
C431553:Eppin protein, human; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D011994:Recombinant Proteins; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen