title: Heparin binding carboxypeptidase E protein exhibits antibacterial activity in human semen.
abstract: Carboxypeptidase E (CPE) cleaves basic amino acid residues at the C-terminal end and involves in the biosynthesis of numerous peptide hormones and neurotransmitters. It was purified from human seminal plasma by ion exchange, heparin affinity and gel filtration chromatography followed by identification through SDS-PAGE and MALDI-TOF/MS analysis, which was further confirmed by western blotting. CPE was characterized as glycoprotein by Periodic Acid Schiff (PAS) staining and treating with deglycosylating enzyme N-glycosidase F. The interaction of CPE with heparin was illustrated by surface plasmon resonance (SPR) and in silico interaction analysis. The association constant (KA) and dissociation constant (KD) of CPE with heparin was determined by SPR and found to be 1.06 × 10(5)M and 9.46 × 10(-6)M, respectively. It was detected in human spermatozoa also by western blotting using mouse anti-CPE primary antibody. 20-100 μg/ml concentration of CPE was observed as highly effective in killing Escherichia coli by colony forming unit (CFU) assay. We suggest that CPE might act not only in the innate immunity of male reproductive tract but also regulate sperm fertilization process by interacting heparin.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Tomar
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University (JNU), New Delhi, India.
authors.forename: Sudhuman
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, India.
authors.forename: Kamaldeep
authors.initials: K
authors.lastname: Gill
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, India.
authors.forename: Sharmistha
authors.initials: S
authors.lastname: Dey
authors.affiliation: Department of Laboratory Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Sarman
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, India. Electronic address: savita11@gmail.com.
authors.forename: Savita
authors.initials: S
authors.lastname: Yadav
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D043423:Carboxypeptidase H / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects; D006023:Glycoproteins; D006493:Heparin / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D012661:Semen / Q000201:enzymology*; D013094:Spermatozoa / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D006023:Glycoproteins; D006493:Heparin; D043423:Carboxypeptidase H
keywords: Antibacterial; CPE; Heparin; Semen