Identification of gp17 Glycoprotein and Characterization of Prostatic Acid Phosphatase (PAP) and Carboxypeptidase E (CPE) Fragments in a Human Seminal Plasma Fraction Interacting with Concanavalin A

Abstract

The decapacitating fraction of human seminal plasma, which strongly interacts with concanavalin A, is constituted by high mannose-type N-linked glycoproteins, most of them of less than 44 kDa. Each component with apparent molecular mass of 30, 18, and 17 kDa respectively, as judged by SDS-PAGE, was submitted to "in gel" digestion with trypsin followed by HPLC separation of the peptides and sequencing. They were characterized at microscale as gp17, an aspartyl protease that possibly contributes to liquefaction of the seminal plasma coagulum, two fragments of human acid phosphatase (17 and 30 kDa, respectively), and a 17-kDa fragment of carboxypeptidase E. Neither the fragments of prostatic acid phosphatase nor that of carboxypeptidase E had been described before in the human seminal fluid. Very weak bands, of apparent molecular masses 44 and 52 kDa, are consistent with presence of small amounts of parent compounds, prostatic acid phosphatase and carboxypeptidase E.

Prostate Secretory Protein of 94 Amino Acids (PSP94) Binds to Prostatic Acid Phosphatase (PAP) in Human Seminal Plasma

“…MS/MS analysis of other protein spots also identified lower molecular weight forms of PAP (spots 11–13); along with carboxypeptidase E (spots 9 and 10) and transthyretin amyloidogenic variants (spots 14 and 15). Presence of lower molecular weight fragments of PAP, together with carboxypeptidase E in the seminal plasma has also been reported by Marquínez et al [32]. Similarly, naturally occurring fragments of PAP are found to be present as amyloid fibrils in the seminal plasma [33].…”

Human Seminal Plasma Abrogates the Capture and Transmission of Human Immunodeficiency Virus Type 1 to CD4 + T Cells Mediated by DC-SIGN

“…Chromatography on concanavalin A (ConA)-Sepharose column (22 by 1 cm; Amersham Pharmacia, Uppsala, Sweden) was performed as previously described (32,34). The bed volume of the column was 5 ml, and the flow rate was 12 ml/h.…”

Isolation and Identification of Concanavalin A Binding Glycoproteins from Human Seminal Plasma: A Step Towards Identification of Male Infertility Marker Proteins

“…Con A recognizes high mannose, hybrid and biantennary complex-type N-glycans [28]. Also, Marquínez et al had demonstrated in their research that the human seminal plasma Con A-interacting fraction shows decapacitating activity [18]. Thus, identification of Con A binding protein fraction of human seminal plasma is of paramount importance for better understanding of fertility related physiological processes.…”

“…Many of the previous studies have successfully applied Con A lectin affinity chromatography to enrich and isolate glycoproteins [14][15][16][17]. More captivatingly, Con A-interacting fraction of human seminal plasma shows decapacitating activity [18]. Thus, the study towards isolation and identification of various proteins of this fraction is of vast importance and may help us in better understanding of fertility related processes.…”