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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the possibility that the generation of hydrogen peroxide (H2O2) by spermatozoa plays a physiological role during capacitation. Capacitation is defined as the incubation period required for fertilization in mammals. Capacitation culminates in an exocytotic event, the acrosome reaction (AR). Mammalian sperm generate H2O2 during aerobic incubation and do not contain catalase, the enzyme that promotes scavenging of H2O2. In the present work we show that added catalase inhibited the AR, while glucose oxidase (GO), an enzyme that generates H2O2, accelerated the onset of the AR. Direct addition of H2O2 also stimulated the AR; catalase inhibited both the stimulation by GO and by H2O2. The onset of the AR was always preceded by the appearance of hyperactivated motility. The stimulation of the AR by H2O2 was manifest 1-2 h after the addition of H2O2. Catalase added at 3 h of incubation was less effective in inhibiting the AR than catalase added at the beginning. Incubation of sperm with catalase prevented the induction of the AR by the membrane-perturbing lipid, lysophosphatidyl choline. Taken together, these results suggest that H2O2 produced by hamster sperm plays a significant role during capacitation, possibly in membrane reorganization to facilitate the fusion that takes place during exocytosis of the acrosomal contents.
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PMID:Hydrogen peroxide is involved in hamster sperm capacitation in vitro. 201 58

Catalase activity was determined in human semen by measuring the oxygen burst with a Clark electrode, after H2O2 addition. Significant catalase activities (mean +/- SD) were found in migrated, motile spermatozoa (44 +/- 17 nmoles O2/min/10(8) cells) and in seminal plasma of normozoospermic men (129 +/- 59 nmoles O2/min/ml). It has been demonstrated that seminal catalase originated from prostate; however, its activity was not correlated with the usual prostatic markers (such as citric acid and zinc). Our data suggest a multiglandular function secreted by this organ. The catalase activities measured in seminal samples from asthenozoospermic, infertile men were found lower than those from normozoospermic subjects. The understanding of the relative contribution of the different enzyme systems against O2 toxicity (superoxide dismutase, catalase, glutathione peroxidase) seem to be a priority area of research to understand disturbances of sperm function.
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PMID:Catalase activity in human spermatozoa and seminal plasma. 279 57

The present study was carried out to determine the localization of peroxidase activity in bull spermatozoa. 3,3'-Diaminobenzidine (DAB) was used as a substrate for revealing peroxidase activity, and light and electron microscopic analysis of the results obtained was performed. Peroxidase activity was detected in the mitochondria of the middle piece and the outer acrosomal membrane. Catalase was excluded as an enzyme, catalyzing the detected peroxidase activity. Concerning the biochemical properties of bull sperm peroxidases, peroxidase activity was found to be manifested in a large pH range, 4-10.5. Bull sperm peroxidase activity appeared to be temperature sensitive and azide sensitive and could be readily inhibited by phenylhydrazine. Electrophoretic analysis of the proteins from bull sperm extracts separated in a Davis-Ornstein system of 7% polyacrylamide gel, followed by the determination of peroxidase activity on the polyacrylamide gels, revealed that all 14 sperm protein fractions available on the gel possessed peroxidase when benzidine was used as a substrate. The possible reasons for the electrophoretic heterogeneity of bull sperm peroxidases are discussed.
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PMID:Peroxidase activities in bull spermatozoa. 817 3

Reactive oxygen species (ROS) can be detected in the semen of 40% of infertile men, whereas none is detected in semen from normal men. The ROS detected in semen are a reflection of the imbalance between ROS production and degradation. The aim of the present study was to determine whether a lowered scavenging capacity or an increased production of ROS was responsible for the ROS detected in semen samples from infertile men. Two activities were investigated: (1) catalase-like activity, which is responsible for the degradation of H2O2 and (2) superoxide dismutase-like (SOD-like) activity which is responsible for the degradation of .O2-. Catalase-like and SOD-like activities were found in whole seminal plasma, in dialyzed seminal plasma (> 12 kD), in an ultrafiltrate of seminal plasma (< 5 kD) and in spermatozoa. There was no significant difference in the SOD-like activities measured in spermatozoa, or in seminal plasma (whole or fractionated) from samples that did or did not produce ROS. SOD-like activity originated mostly from the high molecular weight components of seminal plasma. However, the catalase-like activity of whole seminal plasma and of spermatozoa was significantly greater (P = 0.01) in those samples that produced ROS as compared to those that did not. The catalase-like activity in dialyzed seminal plasma, and an ultrafiltrate of seminal plasma from semen samples that did or did not produce ROS were not statistically different. The catalase-like activity of the seminal plasma originated equally from high and low molecular weight components.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reactive oxygen species in semen of infertile patients: levels of superoxide dismutase- and catalase-like activities in seminal plasma and spermatozoa. 835 32

The influence of nitric oxide on human sperm hyperactivation and capacitation, as well as its mechanism of action and its possible origin from spermatozoa were studied. Percoll-washed spermatozoa from healthy volunteers were incubated in Ham's F-10 medium supplemented or not with the nitric oxide-releasing agents, diethylamine-NONOate or spermine-NONOate, in combination or not with superoxide dismutase or catalase (scavengers for the superoxide anion and for hydrogen peroxide, respectively), or with sodium nitrate, sodium nitrite, or preincubated NONOates. Sperm hyperactivation, capacitation, and nitric oxide synthase activity were determined. High concentrations (0.3 to 1 mM) of NONOates reduced sperm motility. However, a lower concentration (0.1 mM) of the two NONOates had no effect on the percentage of sperm motility or of hyperactivation but resulted in a significant increase in sperm capacitation (24% +/- 4%) when compared to that of control spermatozoa (Ham's F-10 alone, 12% +/- 2%). Nitric oxide released by the NONOates appeared responsible for this effect because sodium nitrate or nitrite or preincubated NONOates (to exhaust the formation of nitric oxide) had no influence on sperm capacitation. Catalase, but not superoxide dismutase, abolished the capacitating action of the NONOates. No nitric oxide synthase activity was detected in spermatozoa, whether they were in their basal state or already capacitated. Furthermore, the nitric oxide synthetase inhibitor L-NG nitroarginine methyl ester did not block sperm capacitation induced by fetal cord serum ultrafiltrate. It is therefore concluded that, although spermatozoa do not possess detectable nitric oxide synthase activity, low levels of nitric oxide induce human sperm capacitation, and this action likely involves hydrogen peroxide.
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PMID:Low levels of nitric oxide promote human sperm capacitation in vitro. 857 82

Hydrogen peroxide (H2O2) is a reactive oxygen species that at low concentration is toxic to sperm. H2O2 inhibits not only sperm viability but also the acrosome reaction, sperm-egg binding, and oocyte penetration. Catalase activates the decomposition of H2O2 into water and oxygen, thus removing an initiator of free radical chain reactions leading to lipid peroxidation. Since the oviduct is known to enhance sperm survival, we hypothesized that it might secrete catalase. We found that oviductal fluid, harvested from washed cells collected at the slaughterhouse, possessed catalase-specific activity that varied during the estrous cycle. Catalase activity increased during the cycle and reached its maximal level just before ovulation (Days 18-20). No significant difference in activity was seen between fluid from the isthmus and that from the ampulla. Indirect immuno-staining of spermatozoa incubated in the oviductal fluid revealed the association of catalase in the region of the acrosomal cap. Addition of a commercial antibody directed against bovine liver catalase completely inhibited catalase activities from the oviductal fluid. Catalase activity was also detected in porcine oviductal fluid, human oviductal fluid, and cervical mucus. Western blots of oviductal fluid probed with the anti-catalase antibody revealed two major bands at 60 and 40 kDa. An immunoaffinity column was used to purify oviductal catalase, showing a unique band at about 60 kDa when analyzed by SDS-PAGE. The purified protein was incubated with bovine, boar, and human sperm, and Western blots of these sperm after several washes detected a band at 60 kDa, indicating that the protein was bound to sperm membranes. However, bovine liver catalase did not bind to sperm. Since H2O2 is one of the key reactants in the chain reaction of free radical production, this enzyme may play an important role in sperm survival within the female tract.
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PMID:Binding of a bovine oviductal fluid catalase to mammalian spermatozoa. 951 Sep 62

The lipid metabolism in sperm cells is important both as one of the main sources for energy production and for cell structure. The double leaflets of the membrane should be considered not simply as a passive lipid film, but as a very specialized structure. The complete maturation of the sperm cell membrane is attained after testicular lipid biosynthetic processes and after passage through the epididymis. A special composition of membrane phospholipids, rich in polyunsaturated fatty acids (PUFA), and the different composition of sperm and immature germ cell membrane are described and discussed. Testis germ cells as well as epididymal maturing spermatozoa are endowed with enzymatic and non-enzymatic scavenger systems to prevent lipoperoxidative damage. Catalase, superoxide dismutase and GSH-dependent oxidoreductases are present in variable amounts in the different developmental stages. Phospholipid hydroperoxide GSH peroxidase (PHGPx) activity and alpha tochopherol of epididymal spermatozoa are considered in detail. Their distribution and roles in caput and cauda epididymal sperm cells are discussed. Seminal plasma also has a highly specialized scavenger system that defends the sperm membrane against lipoperoxidation and the degree of PUFA insaturation acts to achieve the same goal. Systemic predisposition and a number of pathologies can lead to an anti-oxidant/pro-oxidant disequilibrium. Scavengers, such as GSH, can be used to treat these cases as they can restore the physiological constitution of PUFA in the cell membrane. The results of GSH therapy are presented and discussed.
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PMID:Lipoperoxidation damage of spermatozoa polyunsaturated fatty acids (PUFA): scavenger mechanisms and possible scavenger therapies. 1070 76

The objective of this study was to examine the influence of reactive oxygen species (ROS), generated through the use of the xanthine (X)-xanthine oxidase (XO) system, on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation. Equine spermatozoa were separated from seminal plasma on a discontinuous Percoll gradient, and spermatozoa were incubated with 0.6 mM X and 0.05 U/mL XO for 30 minutes. Catalase (150 U/mL), superoxide dismutase (SOD, 150 U/mL), or glutathione (GSH, 1.5 mM) were evaluated for their ability to preserve sperm function in the presence of the induced oxidative stress. At the end of the 30-minute incubation, sperm motility was determined by computer-assisted semen analysis. Viability and acrosomal integrity were determined by Hoechst-Pisum sativum staining, and mitochondrial membrane potential was determined by staining with JC-1. Incubation with the X-XO system led to a significant (P < .01) increase in hydrogen peroxide production and an associated decrease (P < .01) in motility parameters. Total motility was significantly (P < .01) lower in the presence of X-XO compared with the case of the control (29%+/-9% vs 73%+/-1%, respectively). Catalase, but not SOD, prevented a decline in motility secondary to oxidative stress (71%+/-4% vs 30%+/-3%, respectively). The addition of glutathione had an intermediate effect in preserving sperm motility at the end of the 30-minute incubation (53%+/-3%). No influence of X-XO could be determined on viability, acrosomal integrity, or mitochondrial membrane potential. In order to promote lipid peroxidation, samples were incubated with ferrous sulfate (0.64 mM) and sodium ascorbate (20 mM) for 2 hours after the X-XO incubation. No increase in membrane lipid peroxidation was detected. This study indicates that hydrogen peroxide is the major ROS responsible for damage to equine spermatozoa. The decrease in sperm motility associated with ROS occurs in the absence of any detectable decrease in viability, acrosomal integrity, or mitochondrial membrane potential or of any detectable increase in lipid peroxidation.
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PMID:The effect of reactive oxygen species on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation. 1110 16

The lipid metabolism in sperm cells is important both for energy production and for cell structure. A special composition of membrane phospholipids, rich in polyunsaturated fatty acids (PUFA), and the different composition of sperm and immature germ cell membrane are described and discussed. Testis germ cells as well as epididymal maturing spermatozoa are endowed with enzymatic and non-enzymatic scavenger systems to prevent lipoperoxidative damage. Catalase, superoxide dismutase, and glutathione-dependent oxidoreductases are present in variable amounts in the different developmental stages. Phospholipid hydroperoxide glutathione peroxidase (PHGPx) activity and roles in caput and cauda epididymal sperm cells are discussed. Also seminal plasma has a highly specialized scavenger system that defends the sperm membrane against lipoperoxidation and the degree of PUFA insaturation acts to achieve the same goal. Systemic predisposition and a number of pathologies can lead to an anti-oxidant/pro-oxidant disequilibrium. Scavengers, such as glutathione can be used to treat these cases as they can restore the physiological constitution of PUFA in the cell membrane.
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PMID:Polyunsaturated fatty acids of germ cell membranes, glutathione and blutathione-dependent enzyme-PHGPx: from basic to clinic. 1202 Jul 83

Several epidemiological studies and animal experiments showed that 2,4,6-trinitrotoluene (TNT), a commonly used explosive, induced reproductive toxicity. To clarify whether the toxicity results from the interference of endocrine systems or direct damage to reproductive organs, we examined the effects of TNT on the male reproductive system in Fischer 344 rats. TNT administration induced germ cell degeneration, the disappearance of spermatozoa in seminiferous tubules, and a dramatic decrease in the sperm number in both the testis and epididymis. TNT increased the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in sperm whereas plasma testosterone levels did not decrease. These results suggest that TNT-induced toxicity is derived from direct damage to spermatozoa rather than testosterone-dependent mechanisms. To determine the mechanism of 8-oxodG formation in vivo, we examined DNA damage induced by TNT and its metabolic products in vitro. 4-Hydroxylamino-2,6-dinitrotoluene, a TNT metabolite, induced Cu(II)-mediated damage to 32P-labeled DNA fragments and increased 8-oxodG formation in calf thymus DNA, although TNT itself did not. DNA damage was enhanced by NADH, suggesting that NADH-mediated redox reactions involving TNT metabolites enhanced toxicity. Catalase and bathocuproine inhibited DNA damage, indicating the involvement of H2O2 and Cu(I). These findings suggest that TNT induces reproductive toxicity through oxidative DNA damage mediated by its metabolite. We propose that oxidative DNA damage in the testis plays a role in reproductive toxicity induced by TNT and other nitroaromatic compounds.
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PMID:2,4,6-trinitrotoluene-induced reproductive toxicity via oxidative DNA damage by its metabolite. 1215 May 43


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