title: [Correlation of epididymal protease inhibitor Eppin and Semenogelin on human ejaculated spermatozoa].
abstract: 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.
authors.affiliation: Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Zeng-Jun
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Hong-Fei
authors.initials: HF
authors.lastname: Wu
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Qian
authors.forename: Di
authors.initials: D
authors.lastname: Qiao
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Shao
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Yuan-Geng
authors.initials: YG
authors.lastname: Sui
authors.forename: Zheng-Quan
authors.initials: ZQ
authors.lastname: Xu
mesh_terms: 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*
chemical_list: C431553:Eppin protein, human; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D011994:Recombinant Proteins; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen