Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Further evidence is presented that the acrosomal proteinase acrosin exists as a zymogen precursor in freshly ejaculated boar spermatozoa. Autoactivation of proacrosin to acrosin takes place optimally at slightly alkaline pH and in the presence of calcium ions. Activation is considerably accelerated by catalytic amounts of trypsin or highly purified acrosin. A significant acceleration of the activation is also achieved by porcine pancreatic and urinary kallikrein, whereas chymotrypsin, plasmin, thrombin or urokinase showed no effect. Activation can be inhibited by p-amino-benzamidine and p-nitrophenyl p'-guanidino-benzoate. Electrophoretic analysis at different stages of activation revealed that during this process various molecular forms of acrosin are produced, apparently by limited proteolysis.
 ...
PMID:Multiple forms of boar acrosin and their relationship to proenzyme activation. 0 66

Two acid stable proteinase inhibitors are present in bull seminal plasma and washed ejaculated bull spermatozoa. Inhibitor I with a molecular weight of about 8700 (estimated by gel filtration) is a very strong inhibitor of bull sperm acrosin but also inhibits bovine trypsin and chymotrypsin and porcine plasmin; inhibition of porcine pancreatic and urinary kallikrein was not observed. In this respect inhibitor I resembles the well known cow colostrum trypsin inhibitor. Inhibitor II with a molecular weight near 6800 (estimated by gel filtration) inhibits bovine trypsin and chymotrypsin, porcine plasmin and pancreatic and urinary kallikrein as well as bull acrosin. The inhibition specificity of inhibitor II is thus very similar to that of the basic inhibitor from bovine organs (Kunitz-type). In view of the inhibition strength and other characteristics, however, the acid stable bull seminal inhibitors are not identical with the inhibitor from cow colostrum or bovine lung (organs).
 ...
PMID:Characterization of the proteinase inhibitors from bull seminal plasma and spermatozoa. 13 81

Human acrosin was purified to electrophoretically homogeneous forms by acidic extraction of washed ejaculated spermatozoa and gel filtration of the acidic extracts on Sephadex G-75, followed by affinity chromatography on p-amino-benzamidine Sepharose. Human acrosin exists in at least four molecular forms. The apparent molecular weights of three forms were determined to be 64 000, 38 000 and 25 000, respectively. The high molecular weight form is transformed to the low molecular weight forms by incubation of the acrosin preparation obtained from freshly ejaculated spermatozoa in solutions of pH near 7. Like boar acrosin, human acrosin is also a glycoprotein and therefore reversibly bound to Concanavalin A-Sepharose. The amino acid composition of the 25 000 molecular weight form is similar to that of human trypsin. Rabbit anti-boar-acrosin gamma-globulins form a precipitate with human acrosin, but not with porcine trypsin or human plasmin. The relationship between the occurrence of multiple acrosin forms and proenzyme activation by limited proteolysis is discussed.
 ...
PMID:Multiple forms of human acrosin: isolation and properties. 98 58

Using immunoaffinity chromatography on a Sepharose 4B column with adsorbed antibodies to the basic inhibitor in bovine organs (Kunitz-type), a proteinase inhibitor was isolated from boar seminal vesicle fluid. The isolated protein inhibited acrosin, trypsin, plasmin and chymotrypsin, but not kallikrein. Its molecular weight determined by gel filtration on Sephadex G-50 was 9,500 (+/- 500) and by SDS electrophoresis in polyacrylamide gel 12,000 (+/- 500) daltons. The protein was demonstrated by immunoprecipitation only in boar seminal vesicle fluid and seminal plasma, and by indirect immunofluorescence on ejaculated spermatozoa and in the epithelium of boar seminal vesicles. This inhibitor is the first acrosin inhibitor specific for the genital organs, which evidently belongs to the group of Kunitz type inhibitors, to be described.
 ...
PMID:A Kunitz type of proteinase inhibitor isolated from boar seminal vesicle fluid. 293 36

The effect of various proteases (kallikrein, plasmin, and trypsin) on sperm phospholipase A2 activity (PA2: EC 3.1.1.4) has been studied. The addition of trypsin to spermatozoa, isolated and washed in the presence of the protease inhibitor benzamidine, increased PA2 activity optimally with trypsin concentrations of 1.0-1.5 units/assay. In kinetic studies, all of the above proteases stimulated the deacylation of phosphatidylcholine (PC); in fresh spermatozoa, trypsin showed a higher activation potential than kallikrein or plasmin. In the presence of benzamidine, the activity remained at basal levels. Endogenous protease activity due to acrosin (control) resulted in an increase in PC deacylation compared to the basal level. The maximum activation time of PA2 activity by proteases was 30 min. Natural protease inhibitors (soybean trypsin inhibitor and aprotinin) kept the PA2 activity at basal levels and a by-product of kallikrein, bradykinin, did not significantly affect the control level. Protein extracts of fresh spermatozoa exhibited the same pattern of PA2 activation upon the addition of proteases, thus indicating that the increase in PA2 activity was not merely due to the release of the enzyme from the acrosome. All of these findings suggest the presence of a precursor form of phospholipase A2 that can be activated by endogenous proteases (acrosin) as well by exogenous proteases present in seminal plasma and in follicular fluid (plasmin, kallikrein). Thus, this interrelationship of proteases and prophospholipase A2 could activate a dormant fusogenic system: the resulting effect would lead to membrane fusion by lysolipids, key components in the acrosome reaction.
 ...
PMID:Activation of phospholipase A2 of human spermatozoa by proteases. 297 29

In this communication I have attempted to present an overview of some contributions to the understanding of the oviduct-egg interaction in amphibians. According to data from other authors, the vitelline envelope of the newly ovulated egg constitutes a barrier for the passage of spermatozoa. Our results demonstrated that only after they have been affected by substances released by the first 1-3 cm of the oviduct (pars recta), is the envelope sensitive to spermlysins and the oocytes fertilizable. This functional change is matched by biological, physicochemical and morphological differences in the vitelline envelope. The fact that the pars recta activity is affected by the sexual cycle and that in ovariectomized females - devoid of active pars recta - the biological activity can be restored by steroid hormones, strongly suggests that the molecules involved in fertilization are synthesized and secreted during specific steps of the reproductive cycle. The pars recta-oocyte interaction probably involves more than one type of molecules, considering the observations made on the carbohydrate metabolism of coelomic eggs, which could be altered by the oviducal secretions. Several explanations for the pars recta mechanism of action have been suggested. One is a direct action on the sperm; pars recta molecules - engulfed in the vitelline envelope - would trigger the acrosome reaction. We propose the unmasking of specific vitelline envelope sites for sperm interaction. Material on the outer surface of the VE can be removed or altered by the enzymatic activity - similar to plasmin and trypsin - detected in the pars recta secretions.
 ...
PMID:Oviducal pars recta as factor in fertilization properties and hormonal regulation in the toad Bufo arenarum. 310 80

The amino acid sequence of the bovine seminal protein, caltrin, which inhibits calcium transport into spermatozoa, has been determined. The protein contains 47 amino acid residues. Parts of the sequence are identical with that reported for bovine seminal plasmin, a protein possessing antibacterial activity. We believe the proteins are identical and that the previously reported sequence of seminal plasmin is in error.
 ...
PMID:The structure of caltrin, the calcium-transport inhibitor of bovine seminal plasma. 386 8

A new anionic acrosin inhibitor was found in an acidic extract of boar spermatozoa. The protein was purified by hydrophobic and ion exchange chromatography. According to gel filtration and SDS-electrophoresis the inhibitor preparation shows a molecular mass of Mr approximately 6000-7000 daltons. The isoelectric point is close to pH 4.5. It is an effective inhibitor of boar acrosin and bovine trypsin, but it does not inhibit porcine plasmin and pancreatic kallikrein or bovine chymotrypsin. An inhibitor with identical properties was found in high concentration (97% of the total acrosin inhibiting activity) in the fluid of cauda epididymis and also as a minor acrosin inhibiting component (2% of total acrosin inhibiting activity) in seminal plasma. The results indicate that binding of the inhibitor to spermatozoa may have taken place in the epididymis.
 ...
PMID:Demonstration of an anionic acrosin inhibitor in spermatozoa epididymal fluid and seminal plasma of the boar. 390 26

Mature spermatozoa contain a number of proteases that are supposed to contribute to their fertilizing ability. The present study was directed at plasminogen activator (PA), a protease that belongs to the group of serine proteases and converts the zymogen plasminogen to the active broad-spectrum protease plasmin. To investigate the possible role of PA in the fertilization process, we have measured sperm-bound PA activity in 63 patients included in an in-vitro fertilization (IVF) programme and assessed their relationship to standard semen parameters and the rate of fertilization. PA activity was correlated significantly with the sperm count, as well as with sperm motility and morphology. Using logistic regression analysis, specific PA (pmol pNA 10(-6) cells min-2) was found to significantly influence the probability of fertilization. Other significantly predictive factors were motility and the percentage of spermatozoa with normal morphology. The sperm concentration (10(6) cells ml-1) did not significantly affect the outcome of IVF. We suggest that sperm-bound PA is involved in the fertilization process and may represent a potential indicator of sperm fertilizing capacity.
 ...
PMID:Plasminogen activator activity and fertilizing ability of human spermatozoa. 835 35

At the time of fertilization both murine gametes express plasminogen-dependent proteolytic activity: unfertilized eggs secrete tissue-type plasminogen activator and ejaculated spermatozoa have urokinase-type plasminogen activator bound to their surface. We now report that plasminogen is present in the fertilization environment and that both spermatozoa and eggs are able to specifically bind plasminogen. Furthermore, in vitro fertilization of mouse eggs is inhibited by antibodies which inhibit the catalytic activity of plasmin. Finally, with two different in vitro fertilization protocols, the addition of plasminogen to the fertilization medium increases the yield of fertilized eggs. These results provide evidence for a role of the plasminogen activator/plasmin proteolytic cascade in mammalian fertilization.
 ...
PMID:Involvement of the plasminogen activator/plasmin proteolytic cascade in fertilization. 838 18


1 2 3 Next >>