Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inheritance of the mitochondrial genome is known to be exclusively maternal. To determine whether the loss of paternal mitochondria could be due to a deficiency of RNA in the spermatozoal mitochondria, the expression of mitochondrial genes was studied in testicular cells at various stages of spermatogenesis and in epididymal spermatozoa. The presence of mitochondrial transcripts was examined by Northern blot analysis using probes for the following mitochondrially encoded genes: 12 S and 16 S ribosomal RNAs and a group of mRNAs including cytochrome oxidase subunits I and II (COI-COII), cytochrome b (cyt b), adenosine triphosphatase (ATPase) subunits 6 and 8, and subunit 1 of the respiratory chain NADH dehydrogenase (ND1). Comparison of total testicular RNA preparations from prepuberal (6, 8, 12, 16, 18, 20, 22, and 30 days old) and sexually mature (45 days old) mice revealed no major qualitative or quantitative differences in the levels of the mitochondrial transcripts described above. Similar results were observed from enriched preparations of type A and B spermatogonia and interstitial cells obtained from the testes of 8-day-old mice. Transcripts for COI-COII, ATPase 6, or ND1 were reduced in amount in the enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies when compared to the amount in total testis or liver RNA. Transcripts of all the mitochondrial genes analyzed were present in RNA preparations isolated from sperm midpiece tails obtained after sonication of epididymal spermatozoa. These studies demonstrate that (a) during testicular development the levels of mitochondrial RNA in total testicular extracts show no major qualitative and quantitative differences; (b) the mitochondrial transcripts in enriched populations of type A and type B spermatogonia are not different from those obtained from total testes extracts; (c) mitochondrial transcript levels gradually decrease in enriched preparations of pachytene spermatocytes, round spermatids, and residual bodies; and (d) the mitochondrial rRNAs and mRNAs encoded by several mitochondrial genes can be isolated from sperm midpiece tails.
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PMID:Mitochondrial gene expression in male germ cells of the mouse. 277 68

We describe a protocol to isolate a highly enriched fraction of outer acrosomal membrane from guinea pig spermatozoa and present new data on the ultrastructure of this membrane domain. Cauda epididymal spermatozoa were suspended into a low ionic strength buffer and subjected to brief homogenization; this stripped the plasma membrane from the spermatozoa and severed the acrosomal apical segment from the spermatozoon. The crescent-shaped apical segments retained the outer acrosomal membrane and specific components of the acrosomal matrix. Enriched fractions of apical segments were isolated on discontinuous sucrose gradients and the outer acrosomal membrane purified by subsequent centrifugation onto Percoll density gradients. The isolated outer acrosomal membrane did not form vesicles, but instead rolled up into spiral sheets. Both thin section and negatively stained specimens revealed a paracrystalline arrangement of filaments associated with the luminal surface of the membrane. The isolated outer acrosomal membrane revealed a limited number of polypeptides by SDS-PAGE, and the polypeptide pattern was distinct from the plasma membrane fraction. The isolated acrosomal membranes possessed no ouabain sensitive Na+,K+-ATPase activity, whereas about 20% of the ATPase activity of the plasma membrane enriched fraction was inhibited by ouabain. The potential function of the structural differentiations of the outer acrosomal membrane in the membrane fusion events of the acrosome reaction is discussed.
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PMID:Outer acrosomal membrane of guinea pig spermatozoa: isolation and structural characterization. 285 26

Extracellular calcium at millimolar concentrations inhibits collective motility of ejaculated ram spermatozoa. In untreated cells, or when motility was made dependent upon glycolytic activity, there is very small inhibition, but when motility was made dependent upon mitochondrial respiration there is very high inhibition in motility by increasing extracellular Ca2+ concentration. Quercetin, which inhibits (Ca2+ + Mg2+)-ATPase activity in isolated plasma membranes, also inhibits motility mainly in cells that have been made dependent upon glycolytic activity, but there is also inhibition in untreated cells. When motility was made dependent upon mitochondrial activity, there is no inhibition but rather some stimulation in motility by quercetin. The inhibitory effect of quercetin is enhanced by increasing Ca2+ concentration in the medium. Quercetin also inhibits uptake of calcium into the cells, in a mechanism by which a calcium channel is involved. This inhibition is high only when the glycolysis is inhibited in the cells. The rate of glycolysis is decreased by quercetin or ouabain, but their effects on motility are quite different. Based on these data, it appears that the plasma membrane (Ca2+ + Mg2+)-ATPase or the Ca2+ pump have a functional role in the regulation of spermatozoa motility. This motility regulation is functioning through mechanisms which include glycolytic activity and maintenance of intracellular calcium concentrations.
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PMID:The role of calcium and Ca2+-ATPase in maintaining motility in ram spermatozoa. 293 27

The high salt extract obtained from demembranated human spermatozoa contains high molecular weight proteins. These proteins are associated with an ATPase activity inhibited by sodium orthovanadate. In association with lower molecular weight proteins, they constitute a 20 S particle and are probably localized in the dynein arms (and in the radial spokes) of the human spermatozoon axonemes. Evidence is shown for a biochemical analogy between the dynein ATPases extracted from the invertebrate axonemes and the human dynein-like ATPase described in this study.
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PMID:Identification of an ATPase activity associated with the high molecular weight proteins of the human spermatozoon axonemes. 293 98

Energy coupling in flagellar motility was investigated using demembranated, reactivated sea urchin spermatozoa (Arbacia punctulata). The ATP-dependence of ATPase activity was investigated for ATP concentrations ranging from 4 microM to 600 microM ATP. Using Eadie-Scatchard plot analysis, we identified two axonemal dynein ATPase activities. Their apparent Michaelis constants were calculated to be equal to 4 microM and 161 microM ATP, and they were referred to, respectively, as the high-affinity dynein ATPase (HADA) and the low-affinity dynein ATPase (LADA). Investigation of movement-coupled ATPase activity (difference between the ATPase activities of reactivated and broken, immotile spermatozoa) indicated that HADA and LADA were both 65% movement-coupled. The apparent Michaelis constants of movement-coupled HADA and LADA, 12 microM and 271 microM ATP, respectively, were two- to four-fold greater than the apparent Michaelis constants of movement-uncoupled HADA and LADA. The apparent Michaelis constants for force generation and beat frequency of reactivated spermatozoa were determined to be 24 microM and 290 microM ATP, respectively. These results raise the possibility that flagellar force generation is controlled primarily by movement-coupled HADA, and that flagellar beat frequency is controlled primarily by movement-coupled LADA. Thus, mechanochemical activity in flagellar motility may be divided between two enzymatically and functionally distinct classes of flagellar dyneins.
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PMID:Evidence for functional differences between two flagellar dynein ATPases. 294 77

Dialysis of demembranated bull spermatozoa against a low-salt buffer resulted in the solubilization of the outer dynein arms and 15-25% of the total ATPase activity. Low-salt extracts contained three high-Mr peptides with Mr values above 300,000. The ATPase activity was associated with two particles sedimenting at 19 S and 12 S. The heavier particle contained two major high-Mr peptides with Mr values above 300,000, one major and one minor intermediate peptides with Mr values of 91,000 and 140,000 respectively and lower-Mr peptides. The 12 S particle contained one high-Mr peptide positioned between the two heavy peptides of the 19 S particle. Even though the peptide compositions of these two particles were different, the enzymic properties of their ATPases were similar. Both particles hydrolysed in the following preference order: ATP greater than CTP greater than UTP greater than ITP greater than GTP. ATPase activities were not affected by ouabain and oligomycin but were inhibited by vanadate, erythro-9-[3-(2-hydroxynonyl)]adenine and EDTA. Enzyme activities were dependent on the presence of a bivalent cation with the following preference order: Mn2+ greater than Mg2+ greater than Ca2+ greater than Ni2+. Optimal activity was observed between pH 6.5 and 9.5. The Km for ATP ranged from 40 to 50 microM for both 19 S and 12 S ATPases. These results suggest that the 12 S and 19 S particles are dyneins from outer dynein arms.
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PMID:Isolation and characterization of dynein ATPase from bull spermatozoa. 295 Aug 53

An intact organelle, the prostasome, is secreted by the acinar epithelial cell of the human prostate gland. The ultrastructural location of the prostasome is within membrane-bound storage vesicles in the epithelial cells. Prostasomes are delivered into the glandular lumen by an exocytotic event, which is preceded by fusion of adjacent membranes belonging to the storage vesicle and the epithelial cell. Alternatively, the storage vesicle can be translocated in toto from the cell interior into the acinar lumen through the plasma membrane. This latter event has been designated diacytosis. Both phenomena seem to occur with approximately equal frequency in the human prostate gland. An ATPase system that is Mg2+ and Ca2+-dependent is firmly linked to the membranes encasing the prostasomes. The ATPase system may be the molecular basis for vectorial transport of calcium into these organelles. Also a protein kinase activity is located in the membranes. An increase in membrane thickness was observed on phosphorylation. The physiologic function of the prostasomes is not known. They may be important for promoting forward motility of spermatozoa.
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PMID:The prostasome: its secretion and function in man. 299 93

When the spermatozoa of oligoasthenozoospermic patients were suspended with the supernatant of normal semen, an increase in triple ATPase enzyme activities besides enhancement of spermatozoa motilities were observed. This suggests that factor or factors present in the supernatant of normal semen that effects spermatozoa motility also have a positive effect on triple ATPase enzyme activities. In an attempt to produce such an effect, zinc, arginine and fructose were added to the incubation media where the spermatozoal ATPase enzyme activities were determined. Zinc increased Ca2+-Mg2+ ATPase enzyme activity without affecting Na+/K+-Mg2+ and Mg2+ ATPase activities. Triple ATPase enzyme activities remained unchanged after arginine and fructose additions. As a result zinc is thought to be one of the factors that affect spermatozoa motility in seminal plasma.
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PMID:The effect of zinc, arginine, fructose and seminal supernatant of normal semen on the triple adenosine triphosphatase activities of the spermatozoa from males with oligoasthenozoospermia. 299 81

An improved method for the isolation of pure plasma and acrosomal membranes from bull spermatozoa is presented. Plasma membranes were isolated from the spermatozoa of bulls of different breeds, and some enzymatic activity, such as (Na+-K+) ATPase, Ca++ ATPase, Mg++ ATPase, alkaline and acidic phosphatases were assayed. Such enzymatic activity levels differ noticeably from those published by other authors, whose preparations were probably contaminated by other cellular components. Highly statistically significant differences of these activities have been found among the several breeds.
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PMID:Isolation and enzymatic characterization of the plasmalemma from bovine spermatozoa. 299 62

Rats were treated orally with gossypol acetic acid at 30 or 10 mg/kg daily, 6 days a week, for 8, 12, 14 or 16 weeks. At the end of each treatment regimen, treated rats and an equal number of control rats were killed for histological and histochemical studies. From 8 weeks onward, as a result of the treatment, the tubular lumen of the corpus epididymides became narrowed with thickened pseudostratified epithelium and there was a reduction in the amount of spermatozoa. There was an increase in esterase, alkaline phosphatase, acid phosphatase and ATPase activity. These changes increased in intensity with the duration of treatment. Scanning electron microscopic examinations of the corpus epididymides of rats treated for 16 weeks, compared with those of controls, revealed similar changes, namely, narrowing of the tubular lumen, thickening of the pseudostratified epithelium and reduction in the number of spermatozoa.
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PMID:Effect of gossypol acetic acid on the epididymis: histochemical and scanning electron microscope studies. 304 Nov 22


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