Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Acrosin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Studies on ram acrosin. Activation of proacrosin accompanying the isolation of acrosin from spermatozoa, and purification of the enzyme by affinity chromatography.

1. A previously described, freeze-dried, partially purified ram acrosin preparation was fractionated on a column of Sepharose linked to the acrosin inhibitor p-(p'-aminophenoxypropoxy)benzamidine. Two acrosin fractions were obtained. 2. beta-Acrosin was homogeneous, quite stable at low pH and very stable when freeze-dried. Its molecular weight is about 38000, and it contains about six sugar residues per molecule, but no sialic acid. psi-Acrosin consisted of at least three unstable forms of acrosin. 3. When the entire purification process, starting from collection of semen, was carried out as rapidly as possible, the yield of beta-acrosin was increased and very little psi-acrosin was obtained. 4. In fresh ram semen the acrosin is present as the intra-acrosomal zymogen, proacrosin. After its extraction from spermatozoa autoproteolytic reactions convert proacrosin into beta-acrosin; psi-acrosin appears to be breakdown products of beta-acrosin. 5. When beta-acrosin was passed through a column of Sepharose linked to the non-inhibitory deamidinated analogue of the inhibitor it behaved as a hydrophobic protein. This is consistent with our view that acrosin (as zymogen) occurs in spermatozoa as a membrane-bound protein. 6. Success in the isolation of pure acrosin in high yield calls for an affinity adsorbent with the appropriate subsidiary hydrophobic properties.

Acrosin↗
PubMed1994

Sperm-zona pellucida binding of human sperm is correlated with the immunocytochemical presence of proacrosin and acrosin in the sperm heads but not with the proteolytic activity of acrosin.

OBJECTIVE: To determine whether the sperm-zona pellucida (ZP) binding is related to the presence of immunoreactivity for proacrosin and acrosin and/or to the proteolytic activity of acrosin. SETTING: The Andrology Clinic, University of L'Aquila, Italy. PATIENTS: Thirty-five infertile couples and 15 men of proven fertility. INTERVENTIONS: Salt-stored unfertilized oocytes after IVF were inseminated with a mixture of equal numbers of test and fertile donor sperm after swim-up selection, respectively labeled with fluorescein or rhodamine. Total acrosin activity, the percent of sperm immunostained for proacrosin and acrosin, and the percent of sperm with oval heads were evaluated in fresh semen and after swim-up selection. MAIN OUTCOME MEASURES: Three zonae were used for each patient and sperm-ZP binding ratio (ZP ratio) was calculated as the total number of test sperm bound to ZP divided by the total number of control sperm bound to ZP. The ZP ratio was compared with the percent of live sperm immunostained for proacrosin and acrosin, with total acrosin activity and with the percent of sperm with oval heads after swim-up selection. RESULTS: The sperm-ZP binding ratio was correlated positively with the percent of sperm immunostained for proacrosin and acrosin and with the percent of sperm with oval heads, but not with acrosin activity. Ejaculates with immunostaining for proacrosin and acrosin > or = 55% of sperm (the mean value of infertile couples) and acrosin activity < 24 muIU/10(6) sperm (the mean value of infertile couples) (n = 8) had a ZP ratio > or = 0.5, whereas ejaculates with low immunostaining for proacrosin and low acrosin activity (n = 12) had a ZP ratio < 0.5. The difference between the ZP ratio of the two groups was highly significant. CONCLUSIONS: The ZP binding is related to the immunocytochemical presence of proacrosin and acrosin but not to the proteolytic activity of acrosin in human sperm, suggesting that egg recognition and proteolytic activity are independent functions of proacrosin and acrosin.

Acrosin↗
PubMed1976

Effects of acrosin inhibitors on the soluble and membrane-bound forms of ram acrosin, and a reappraisal of the role of the enzyme in fertilization.

When denuded ram spermatozoa were suspended in weakly buffered 0.25M sucrose, the acrosin remained bound to the acrosomal membranes of the sperm heads. Media containing CaCl2 caused complete solubilization of the enzyme. Effects of acrosin inhibitors on soluble and bound enzyme were studied in Tris HCl(pH 8.2) containing sucrose. Denuded spermatozoa were used as a preparation of bound acrosin. Trasylol (Kunitz basic pancreatic trypsin inhibitor) acted more strongly on bound scrosin than on soluble acrosin, but soya-bean trypsin inhibitor acted more strongly on soluble acrosin. At concentrations 0.5 - 2.0muM, the inhibitors isolated from ram acrosomes and from ram seminal plasma inhibited soluble acrosin but had negligible effects on bound acrosin. However, bound acrosin was sensitive to high concentrations of the acrosomal inhibitor. The two forms of acrosin were inhibited to about the same degree by p-aminobenzamidine and also by Tos-Lys-CH2Cl. It is proposed that membrane-bound acrosin is the form that functions in penetration of the zona pellucida, and that a role for acrosin inhibitors is suppression of an antifertility effect of soluble acrosin on mammalian eggs. This hypothesis is supported by 1) the results of work on the impaired fertilizing capacity of rabbit spermatozoa that have been treated with acrosin inhibitors, 2) the anti-fertility effects on hamster eggs of solutions of acrosin and of bovine trypsin, and 3) the results in this paper.

Acrosin↗
PubMed1982

The interaction of ram proacrosin and acrosin forms with antiserum raised against ram m beta-acrosin.

An antiserum was raised in rabbits to pure m beta-acrosin, the stable form of active acrosin from ram spermatozoa. By use of immunoprecipitation with Protein A-bearing Staphylococcus aureus cells, so as to react antigen with antibody and isolate the complex rapidly, it could be demonstrated that the anti-m beta-acrosin cross-reacted strongly with native proacrosin, with a degenerate proacrosin form, and with at least one form of active acrosin other than m beta-acrosin. Sperm proteins unrelated to acrosin were not recognized. It is concluded that rabbit anti-m beta-acrosin will react specifically with all the major ram acrosin forms; the antiserum can therefore be used with confidence in immunocytochemical studies to locate both proacrosin and acrosin in ram spermatozoa.

Acrosin↗
PubMedDate not supplied

On the teratogenesis of round-headed spermatozoa: investigations with antibodies against acrosin, an intraacrosomally located acrosin-inhibitor, and the outer acrosomal membrane.

Acrosin, the outer acrosomal membrane (OAM) and an acrosin inhibitor were studied in testicular cells and ejaculated spermatozoa of fertile men and in those of an infertile patient with exclusively round-headed spermatozoa in his ejaculates. The investigations were performed with the aid of immunohistochemical techniques using specific antibodies against the three acrosomal markers isolated from boar spermatozoa. The spermatozoa of fertile men exhibit staining for acrosin, the OAM and the acrosin inhibitor in the cap region while the round-headed spermatozoa of the patient are totally negative for the three markers, clearly supporting the conclusions of other authors that round-headed spermatozoa lack acrosomes. The lack of the acrosin system was further substantiated by the gelatin substrate film technique. In the course of normal human spermatogenesis acrosin, the OAM and the acrosin inhibitor we first demonstrable in early round spermatids, namely in identical compartments adjacent to the cell nucleus. During spermatid differentiation the staining for the three markers becomes flattened over the nucleus, resulting in a cap-like structure in testicular spermatozoa. In contrast to the ejaculated round-headed spermatozoa, the early round spermatids in the testis of the infertile patient exhibit fluorescent staining for the three markers in the region adjacent to the nuclear membrane. In the course of further spermiogenesis, the staining did not extend over the nuclear membrane, as was observed during normal spermiogenesis, but became separated from the nuclear membrane, as was observed during normal spermiogenesis, but became separated from the nuclear membrane, was translocated at various locations in the cytoplasm and was finally eliminated with the loss of the cytoplasm. These results are in accordance with the results of electron microscopically investigations on the teratogenesis of round-headed spermatozoa. Furthermore, the developmental pattern of the acrosin inhibitor during normal and abnormal spermiogenesis supports the intraacrosomal location of the acrosin inhibitor recently described by Tschesche et al. (1982).

Acrosin↗
PubMed1978

Boar malpha-acrosin. Purification and characterization of the inital active enzyme resulting from the conversion of boar proacrosin to acrosin.

The preparation of highly purified malpha-acrosin is described. Purification was achieved by controlled activation of partially purified proacrosin, followed by gel chromatography over Sephadex G-100 at pH 3.0. The final malpha-acrosin preparation resulted in a single protein band with a molecular weight of 49,000 as determined by sodium dodecyl sulfate-disc gel electrophoresis. Disc arginine naphthylamide hydrolyzing band with a relative migration of 0.39 malpha-acrosin catalyzed the hydrolysis of synthetic substrates containing arginine and lysine, but not phenylalanine. Although calcium ions were not required for enzymatic activity, the addition of calcium chloride stimulated the activity through an increased substrate affinity and an increased maximal velocity. Polyamines stimulated the maximal velocity of the reaction, but were without effect on the substrate affinity. malpha-Acrosin was inhibited by lima bean, ovo-mucoid, and seminal plasma proteinase inhibitors. Diisopropyl fluorophosphate and 1-chloro-3-tosylamide-7-amino-L-2-heptanone treatment resulted in an irreversible inhibition, while L-arginine, benzamidine, and p-aminobenzamidine were competitive inhibitors with respect to substrate. These properties of malpha-acrosin are very similar to those previously reported for mbeta-acrosin and suggest that the portion of the molecule lost during the conversion of malpha-acrosin to mbeta-acrosin contributes little to the topography of either the active site or regulatory sites of the enzyme.

Acrosin↗
PubMed1990

Determination of active, non-zymogen acrosin, proacrosin and total acrosin in different andrological patients.

A spectrophotometric assay is described which, due to improved extraction conditions, allows quantitative determination of enzymatically active, non-zymogen acrosin, proacrosin and total acrosin activity from human sperm acrosomes. Acrosomal proteinase activity is assessed by acid extraction of the sperm pellet and the suspension medium before and after snap-freezing, followed by zymogen autoactivation. Release of acrosin from the acrosome can be used as a sensitive biochemical marker to characterize acrosomal membrane stability, severe disturbance of which may be the cause of impaired male fertility. Acrosin activities in different populations of semen specimens are reported and compared to data available in the literature. Different degrees of acrosomal membrane alterations are observed in men with oligozoospermia, tetratozoospermia and polyzoospermia. Particularly in oligozoospermia, a significant increase of active, non-zymogen acrosin points to severe acrosomal membrane alterations and, in addition, to a premature activation of proacrosin, which may impair fertilization in certain individuals. Finally, acrosin activity is shown to be significantly influenced by the time of sexual abstinence. It is concluded that determination of acrosin may be a useful indicator of the fertility potential in men.

Acetates↗
PubMed1976

Influence of boar acrosin antibodies produced in rabbit and sheep on chymotrypsinogen activation catalyzed by acrosin from boar, bull, ram, rabbkt and human.

Activation of bovine chymotrypsinogen is catalyzed with increasing velocity by human, rabbit, boar, bull and ram acrosin. Antiboar-acrosin rabbit gamma-globulins cause a significant reduction in the proenzyme activation rate induced by boar and bull acrosin, but only a weak reduction or none if ram or rabbit acrosin is the activating agent. The antiboar-acrosin gamma-globulins from sheep strongly inhibit chymotrypsinogen activation by ram, bull and boar acrosin, and significantly inhibit the human acrosin-catalyzed reaction.

Acrosin↗
PubMed1985

Evidence for multiple catalytic sites of human acrosin from kinetic evaluation of fructose-induced acrosin inhibition.

Acrosin (acrosomal proteinase; EC 3.4.21.10) is a sperm-specific serine proteinase implicated in sperm penetration of the mammalian oocyte. Previously, we had shown that human acrosin, unlike human trypsin (EC 3.4.21.4), was inhibited by beta-D-fructose and related carbohydrates. The present study was undertaken to more fully elucidate the mechanism of action of fructose as an acrosin inhibitor, and to further differentiate the kinetic properties of acrosin from those of trypsin. Fructose produced a complex pattern of inhibition. At relatively low concentrations (10-60 mM), fructose acted as a competitive inhibitor with an apparent inhibition constant of 13 mM. In contrast, at high concentrations (80-320 mM), fructose behaved as a noncompetitive inhibitor, with an apparent inhibition constant of 205 mM. A Hill plot of enzyme activity as a function of fructose concentration suggested only a single binding site for fructose (slope = -0.90). The pattern of inhibition is not consistent with an enzyme containing only a single catalytic site, based either upon steady-state or rapid equilibrium assumptions; however, good agreement between observed and simulated data were obtained based upon the assumption of two catalytic sites with equal or similar binding and catalytic constants. The data suggested that fructose interacts with a single binding site (Ki = 8 mM) which alters both catalytic sites to produce an enzyme species having a higher apparent Michaelis constant and lower kcat as compared to the uninhibited enzyme. Fructose had no effect upon the rate of acrosin inactivation by either diisopropylfluorophosphate or tosyl-lysine-chloromethylketone, suggesting that neither substrate binding nor acylation were altered by this agent. The above data indicate substantial differences between the catalytic properties of human acrosin and those of trypsin.

Acrosin↗
PubMed1990

Zona pellucida-binding of boar sperm acrosin is associated with the N-terminal peptide of the acrosin B-chain (heavy chain).

Recently, it has been shown that boar acrosin exhibits a carbohydrate-binding activity with a specificity to fucose, by which it can bind to the oocyte zona pellucida. By limited autoproteolysis of a high-molecular mass acrosin (55/53 kDa), designated as alpha-acrosin, a 15 kDa fragment was generated which interacts strongly with the porcine zona pellucida. Zona-binding was demonstrated on protein blots and by the solid-phase zona-binding assay utilizing biotinylated zona proteins. The zona-binding peptide was isolated by reversed-phase HPLC and analyzed for amino acid sequence. Its single N-terminal sequence corresponded to that of the acrosin B-chain (heavy chain). These data indicate that the zona-binding properties of acrosin are associated with the N-terminal peptide of the acrosin heavy chain.

Acrosin↗
PubMed1982

Inhibition of human and bovine sperm acrosin by divalent metal ions. Possible role of zinc as a regulator of acrosin activity.

Human and bovine spermatozoa have been collected and washed repeatedly with isotonic saline to remove seminal plasma inhibitors and activate the acrosin. Then the acrosin activity of the cells was assayed with alpha-N-Benzoyl-DL-Arg-beta-naphthylamide (BANA). It was found that the surface-bound enzyme was not inhibited by high molecular weight inhibitors of trypsin but was markedly inhibited by low molecular weight trypsin inhibitors. Divalent metals (Zn++, Cu++, Hg++, Co++, Cd++) were all efficient inhibitors of acrosin on the washed cells. It was shown that the removal of zinc or copper from acrosin completely restored activity. It is proposed that the different levels of zinc in the male and female genital tract regulate acrosin activity. Aged cells released a soluble acrosin which was inhibited by serum and seminal plasma inhibitors of trypsin-like enzymes as well as by zinc ions in an identical manner to the surface-bound enzyme.

Acrosin↗
PubMed1981

Studies on acrosin. I. Purification and characterization of boar acrosin.

Acrosin was extracted from boar sperm and purified by Sephadex gel filtration and affinity chromatography on Phe-Phe-Arg Sepharose 4B in acidic condition. Its enzymic properties were characterized in comparison with trypsin. The oligopeptides with Arg at the carboxy-termini were used as the ligands for affinity chromatography. Phe-Phe-Arg adsorbed acrosin at pH 5 and released in at pH 3. To adsorb acrosin, it was found that the ligand should be longer than tripeptide with Arg in the carboxy-termini. Disc gel electrophoretogram of purified boar acrosin gave a broad band consisted from three fractions which hydrolysed N-alpha-benzoyl-arginine ethylester (BAEE). The pH optimum and inhibition spectra were similar to those of trypsin, however, the influence of urea on them were very different among each other. Calcium ion decreased Km for BAEE, and increased Ki of aprotinin. The kinetic analysis of acrosin for its substrate and products resulted that Km for BAEE was minimal at around pH 8 and maximal at pH 5, on the contrary, Ki of the product was low at pH 5, but progressively increased along the elevation of pH. The same tendency was observed for trypsin. From the attitudes on the affinity chromatographies and the pH profiles of kinetics parameters, it was concluded that the active sites of acrosin and trypsin were similar to each other.

Acrosin↗
PubMed1976

Activation of chymotrypsinogen by boar acrosin and its prevention by antiboar acrosin rabbit gamma-globulins.

Activation of chymotrypsinogen by bovine trypsin or boar sperm acrosin was followed up using Nalpha-acetyl-L-tyrosine ethyl ester in a highly sensitive test system. Inhibition studies employing antiboar acrosin rabbit gamma-globulins showed the following results. 1) Whereas the acrosin-induced activation velocity was significantly depressed in the presence of the antibodies, the trypsin-catalyzed activation rate was not diminished. 2) The antibodies enhanced the acrosin-catalyzed cleavage rate of BzArgOEt significantly, but not the trypsin-catalyzed cleavage rate of this substrate. 3) Autodigestion of acrosin was considerably reduced in the presence of the antibodies. The enzymatic test system used is especially suitable to study the specificity of acrosin antibodies or their affinity to related enzymes if only small amounts of these substances are available.

Acrosin↗
PubMed1978

Inactivation of boar acrosin by peptidyl-arginyl-chloromethanes. Comparison of the reactivity of acrosin, trypsin and thrombin.

A survey of the reactivity of 16 peptidyl-argininyl-chloromethanes with boar acrosin indicated that these compounds as a general group of reagents were highly effective in the inactivation of acrosin since at least half of the reagents tested rapidly inactivated this protease at a concentration of 0.10 micrometer or lower. For example, Dns-Glu-Gly-ArgCH2Cl inactivates acrosin by 50% in 1.8 min at a concentration of 75 nM, whereas in contrast, a 14000-fold higher concentration of Nalpha-tosyllysyl-chloromethane is required to obtain an equivalent rate of inactivation. A comparison of the reactivity of acrosin and trypsin with the peptides of arginyl-chloromethane containing different substituents in the P2 and P3 positions suggests that the secondary binding sites of these two proteases are very similar. Reagents with homoarginine, lysine and D-arginine in the P1 position have also been prepared and evaluated, but these were considerably less effective than the corresponding arginyl-chloromethanes in the inactivation of both acrosin and trypsin.

Acrosin↗
PubMed1998

Characterization of mouse epididymal acrosin: comparative studies with acrosin from boar and human ejaculated spermatozoa.

Acrosin is an acrosomal protease believed to play a major role in fertilization. It is synthesized as an inactive precursor, proacrosin, which is processed via (auto)proteolysis into active form(s). In this paper, comparative studies on the characteristics of acrosin from mouse, boar and human are reported. The mouse proacrosin/acrosin was especially investigated to clarify whether or not the enzyme undergoes modifications during epididymal maturation. Acrosomal extracts from mature and immature mouse spermatozoa, as well as from ejaculated boar and human spermatozoa, were analysed by means of SDS-electrophoresis, Western blot and activity measurements. The studies showed that epididymal maturation produced a shift in the molecular weight of proacrosin. It was also observed that the activation kinetics differ strongly between the three species studied. Human proacrosin showed a constant substrate turnover, acrosin from boar showed sigmoidal activation kinetics and mouse acrosin, either from the caput or the cauda epididymides, showed a rapid decay in activity, suggesting the presence of an endogenous specific inhibitor.

Acrosin↗
PubMed2002

[Effect of acrosin inhibitor KF-950 on acrosin activity and acrosome of human sperm].

OBJECTIVES: To study the inhibitory effect of KF-950 on human acrosin and sperm acrosome. METHODS: Human acrosin was extracted and purified with 2% acetic acid, and its residual activity was evaluated by BAEE/ADH assay after treated with different concentrations of KF-950. ABC assay was used to observe the effect of KF-950 on human acrosome with Biotin-PSA as a probe. RESULTS: 1. The activity of normal sperm acrosin was (37.65 +/- 4.47) U/L. 2. The residual activity was inversely related to the concentration of KF-950 (r = -0.998), and had a dose-response curve. The result could be described by Y = 7.57-1.895X. 3. With increase of KF-950 concentration and prolongation of action time, the staining rate of acrosome obviously dropped (P < 0.01). CONCLUSIONS: KF-950 directly inhibits acrosin activity and assumely injures sperm acrosome. It might be a new kind of highly effective inhibitor.

Acrosin↗