Fibrinogen-Like Substance and Thrombin-Like Enzyme in Human Seminal Plasma: Coagulation System of Human Semen

Amidolytic Activities and Prostate-Specific Antigen in Human Seminal Plasma

“…This reaction mechanism is believed to be caused by coagulated proteins discharged from the seminal vesicle and proteinases from the prostate gland [16]. We have already demonstrated that the coagulation and liquefaction processes of human semen are governed by mechanisms similar to the blood coagulation and fibrinolytic systems, respectively, in that thrombin, t-PA and plasminogen/plasmin in the semen constitute a proteinase cascade system [17,21]. …”

“…We found significant correlations among the concentrations of individual amidolytic activities measured in this investigation ( Figure 1, Table 1), suggesting that the physiological roles of these amidolytic enzymes measured are strongly correlated. The presence of proteolytic enzymes in the human seminal plasma has been confirmed, which show synthetic peptidyl arginine amido or ester hydrolyzing activity and Val-CHA-Arg-pNA amidolysis or benzoyl-L-arginine ethyl ester (Bz-Arg-Et) esterolysis, such as tissue kallikrein [7], plasmin [18], t-PA [21], thrombin [21], and basic and acidic arginine amidases [12,13,17]. Of these, plasmin, t-PA, and thrombin constitute the proteinase cascade that is involved in the coagulation and liquefaction process of human semen [18,24].…”

“…Many hydrolytic enzymes, including limited hydrolyzing proteinases and peptidases, are detected in the seminal plasma and appear to play certain roles in various enzymatic functions in the fertilization process, including acrosomal reaction [20,23], dissolution of the zona pellucida [8], and a liquefaction mechanism of ejaculated semen [18,21]. Certain trypsin-like enzymes with amidolytic activity against synthetic arginine and lysine derivatives are found in the semen (seminal plasma), including tissue kallikrein (EC 3.4.21.35) [7,17], tissue plasminogen activator (t-PA, EC 3.4.21.68) [2,15,21,24], and plasminogen/plasmin (EC 3.4.21.7) [14,18,24]; and basic arginine amidases from human and dog were reported by our group [12,13,17] and Frenette et al [5,6]. Seminin [22], which shows chymotrypsin (EC 3.4.21.1) -like amidolytic enzyme activity, appears to control the liquefaction of human semen, but the details are not known.…”

“…Seminin [22], which shows chymotrypsin (EC 3.4.21.1) -like amidolytic enzyme activity, appears to control the liquefaction of human semen, but the details are not known. The human semen liquefaction processes are under the control of the proteolytic enzyme cascade systems, as are coagulation and fibrinolysis in the blood [21].…”

Recent Advances in Andrology Research: Physiopathology and Clinical Application to Fertility and Infertility

“…The liquefaction of human semen is strongly retarded by the powerful synthetic inhibitors of 6-amidino-2-naphtyl-p-guanidinobenzoate dimethansulfonate (FUSAN) and trans-amino caproic acid (t-AMCA) for plasminogen and plasmin, revealing that the plasminogen/plasrnin present in seminal plasma is closely involved in the liquefaction of human semen, analogous to that in the blood fibrinolysis system. A fibrinogen-like substance acts as a coagulation material for semen as in the final stage of the blood coagulation process [55].…”