Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.5 (5'-nucleotidase)
3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain phosphatases have been localized by histochemical techniques in various tissues of a pigeon cestode, Raillietina (Raillietina) johri. Acid phosphatase (AcPase), alkaline phosphatase (AlPase) and adenosine triphosphatase (ATPase) were present in almost all structures: tegument; subtegumental muscles; subtegumental cells; excretory canal; testes; sperm ductules; vas deferens; cirrus sac; cirrus; ovary; receptaculum seminis; vagina; vitelline gland cells; oocytes; uterus; embryonated eggs. AlPase was absent in parenchyma, spermatocytes, spermatids and spermatozoa. AlPase activity was more intense in the tegument of mature gravid proglottides. AcPase and ATPase were visualized in various stages of spermatogenesis of the parasite. ATPase activity was also observed in chromosomes. 5'-nucleotidase (AMPase) activity was restricted to embryonated eggs only. Functional significance of these phosphatases is discussed.
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PMID:Histochemical studies on Raillietina (Raillietina) johri (Cestoda: Davaineidae). I. Nonspecific and specific phosphatases. 22 30

The seminal vesicles originate in embryos of about 58 mm crown-rump-length from the Wolffian duct under the influence of testosterone. Along with the ampulla of the vas deferens and the ejaculatory duct, they form a functional unit that develops slowly until the onset of puberty. Developmental malformations occur as uni- or bilateral agenesis, aplasia, cysts, or ureterovesicular fistules. After puberty, the glands form sac-like structures which have a capacity of about 3.4-4.5 ccm and contribute about 70% of the seminal fluid. In addition to secretion, they are capable of reabsorption of fluids or dissolved substances, and of spermatophagy (ingestion and degradation of damaged spermatozoa by epithelial cells). Secretory activity of the glands is a measure of testosterone supplementation to the epithelium. Nervous regulation of secretion is realized by cholinergic post-ganglionic, sympathetic (and perhaps parasympathetic) fibres, derived from pelvic plexus. Contraction of the muscular wall occurs under the influence of excitatory adrenergic and modulatory NPY-encephalin-peptidergic nerve fibres. The secretory products of the seminal vesicles encompass (1) ions (K+: 1.1 mM ml-1) (2) low molecular weight substances (fructose: above 1.2 mg ml-1; prostaglandins above 250 microliters ml-1, (3) peptides (endorphin: 330 pg ml-1), and (4) proteins. In addition to plasma protein related forms such as transferrin, lactoferrin, and fibronectin, specific proteins such as semenogelin (52 kDa) are synthesized, the scaffold protein of semen coagulate forming the substrate for PSA (prostate specific antigen), sperm motility inhibitor (ca. 18 kDa), and others (placental protein 5, protein kinase inhibitor, carboanhydrase, 5'-nucleotidase), some of which are immunosuppressive. Therefore, functions of the seminal vesicles concern (a) formation of seminal coagulum, (b) modification of sperm functions (motility, capacitation), and (c) immunosuppression. Additional functions within the female genital system, perhaps during pre-implantation period, are likely, but remain to be proven experimentally.
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PMID:Morphology and functions of the human seminal vesicle. 164 33

An improved aqueous two-phase polymer method has been developed for the isolation of sperm plasma membranes by manipulating various parameters that influence markedly the purity as well as yield of the membrane. The method consists of hypotonic shock of intact spermatozoa with 1.25 mM EDTA to dissociate the plasma membrane and dispersion of these cells to a two-phase polymer system consisting of 5.5% 252-Kd dextran and 4.2% 20-Kd polyethylene glycol prior to centrifugation at 9700 X g for 30 min when the two polymer phases are separated; the membrane fraction sediments at the interphase. The resulting membrane fraction was purified further by repeating the two-phase fractionation step. The yield of the membranes was approx. 35-40%, based on the recovery of the membrane-bound marker enzymes alkaline phosphatase and 5'-nucleotidase. The isolated membranes showed a high degree of purity as evidenced by phase contrast and electron microscopic studies and analyses of marker enzymes characteristic of cellular organelles. The yield and purity of the membranes have been found to be markedly dependent on the conditions of the hypotonic shock, obtained as a function of, EDTA concentration and on the molecular sizes of the dextran and polyethylene glycol that constitute the two-phase polymer system, as well as on the centrifugal force used for the sedimentation of the membrane.
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PMID:Factors influencing the yield and purity of goat sperm plasma membranes isolated by means of an aqueous two-phase polymer system. 244 37

Plasma membrane (PM), primarily from the anterior sperm head, and outer acrosomal membrane (OAM), were isolated from ejaculated bovine spermatozoa, and the major lipid classes were characterized. Whole sperm (WS) lipids were analyzed for comparison. PM was removed by nitrogen cavitation and purified by sucrose density-gradient centrifugation. The OAM was removed by centrifugation through hyperosmotic sucrose and recovered by sucrose density-gradient centrifugation. The PM contained primarily spherical vesicles from the region overlying the OAM and was enriched 9- and 13-fold in 5'-nucleotidase and alkaline phosphatase activity, respectively, compared to the original cavitate. The OAM was recovered as caplike structures with associated ground substance. Protein, phospholipid, and cholesterol (PR, PL, and CH as micrograms/5 x 10(9) sperm) were 300, 467, and 93 for PM and 276, 111, and 25 for OAM, respectively. Corresponding values for WS (mg/5 x 10(9) sperm) were 31.4, 6.63, and 0.72. The PR/PL (w/w) and CH/PL (mol/mol) ratios were 0.66 and 0.38 for PM; 2.48 and 0.26 for OAM; and 4.39 and 0.22 for WS. Cholesterol was the only free sterol detected by gas/liquid chromatography in WS, PM, and OAM, with traces of CH sulfate present in all three preparations. Glycolipid tentatively identified as sulfogalactolipid was detected by thin-layer chromatography (TLC) in PM but not OAM. Phospholipid composition of WS and membranes was determined by TLC. Cardiolipin (3% of total PL) was present in WS only. Choline, ethanolamine, and inositol phosphoglycerides (CP, EP, PI, PIP, PIPP); sphingomyelin (SP); phosphatidylserine (PS); and lysophosphatidylcholine (LPC) were present in WS, PM, and OAM. Approximately 50% of total PL was CP in all preparations; SP was 13% of PL in PM and 17% in OAM (p less than 0.05); EP was 7% of PL in PM and 10% in OAM (p less than 0.05). The differences in composition between PM and OAM is discussed with respect to capacitation and ability of sperm to undergo the acrosome reaction.
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PMID:Lipids of plasma membrane and outer acrosomal membrane from bovine spermatozoa. 283 8

The enzymes of adenosine metabolism were investigated in suspensions of epididymal mouse spermatozoa incubated under conditions which support capacitation in vitro. High levels of adenosine deaminase activity were found in sperm suspensions, but the enzyme was located in the surrounding medium and was not intrinsic to spermatozoa. 5'-Nucleotidase was also present in the surrounding medium while in sperm cells it existed as an ecto-enzyme. Adenosine was not metabolized by washed spermatozoa under conditions used for the assay of adenosine deaminase or adenosine kinase, but it was metabolized rapidly by unwashed sperm suspensions. Incubation of sperm suspensions in conditions which modulate fertilizing ability resulted in small alterations in intrinsic 5'-nucleotidase activity of spermatozoa. In contrast, the activity of adenosine deaminase was not consistently modulated by such manipulations. Adenosine deaminase and 5'-nucleotidase exhibited similar kinetic parameters to enzymes from other sources and their activities were inhibited by coformycin and alpha, beta-methylene adenosine 5'-diphosphate, respectively. These studies highlight the low adenosine-metabolizing ability of spermatozoa coupled with the extensive metabolism in the medium which surrounds them. Extracellular adenosine metabolism can therefore occur and may modulate capacitation in vitro.
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PMID:Enzymes of adenosine metabolism in mouse sperm suspensions. 284 Apr 94

The effect of inhibiting adenosine-metabolizing enzymes on sperm fertilizing ability was studied to investigate a possible role for endogenously generated adenosine in the regulation of capacitation. The compounds used have been shown to be effective inhibitors of the relevant enzymes in similarly incubated mouse sperm suspensions. Inhibition of 5'-nucleotidase activity with alpha, beta-methylene adenosine 5'-diphosphate (AMPCP), to reduce available endogenous adenosine, caused a dose-dependent inhibition of the fertilizing ability of partially capacitated spermatozoa, which was significant with 100 and 250 microM AMPCP. Conversely, inhibition of adenosine deaminase with 100 nM coformycin, to increase available endogenous adenosine, promoted the fertilizing ability of partially capacitated spermatozoa when the fertilization rate of control suspensions was low. However, coformycin had no effect on sperm suspensions with moderate fertilizing ability, and it inhibited fertilizing ability when added to capacitated spermatozoa. These data are consistent with a promotion of the early stages of capacitation by endogenously generated adenosine and suggest that sensitivity to adenosine changes as capacitation proceeds. Because the majority of adenosine-metabolizing enzyme activity residues in or is directed toward the extracellular compartment in such suspensions, these effects of adenosine may be mediated at the outer surface of the cell. By interacting with receptors on adenylate cyclase, externally produced adenosine could modulate intracellular levels of cyclic adenosine monophosphate (cAMP), thereby influencing fertilizing ability.
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PMID:Inhibition of adenosine-metabolizing enzymes modulates mouse sperm fertilizing ability: a changing role for endogenously generated adenosine during capacitation. 285 33

The plasma membranes of ram spermatozoa were disrupted in a hypotonic EDTA medium and isolated by using a two-phase polymer system of dextran--polyethyleneglycol. The plasma membranes obtained were of a relatively high degree of purity (approximately 70%) as judged by electron microscopy observations and measurements of the marker enzymes alkaline phosphatase, ATPase and AMPase. The activity of succinate cytochrome C reductase, a marker of mitochondrial membranes, was very low.
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PMID:Isolation of plasma membranes from ram spermatozoa by a two-phase polymer system. 616 59

Adult rat testis homogenates were fractionated by differential centrifugation followed by two discontinuous gradient centrifugation steps under identical conditions except for the absence of digitonin in the first gradient and the presence of 0.03% digitonin in the second gradient. The first gradient centrifugation yielded a membrane fraction enriched 28.8-fold in 5'-nucleotidase, 21.5-fold in UDP-Gal:GlcNAc galactosyltransferase and 18.6-fold in UDP-GlcNAc:alpha-D-mannoside N-acetylglucosaminyltransferase. Repeat centrifugation of this membrane fraction in the denser level of the gradient; this material was enriched 32.1-fold in 5'-nucleotidase but only 1.9-fold in galactosyltransferase and 8.4-fold in N-acetylglucosaminyltransferase. The plasma membrane fraction was shown to be free of glucose-6-phosphatase, succinate dehydrogenase, beta-N-acetylglucosaminidase, DNA, and RNA. The fraction therefore appears to be enriched in plasma membrane but relatively free of Golgi membrane contamination, as indicated by the relatively low levels of glycosyltransferases, and of contamination by other organelles. The testicular cells which contribute plasma membrane to this fraction have not yet been definitively identified; the contribution by Sertoli cells is particularly difficult to assess since these cells have been reported to be enriched in 5'-nucleotidase. However, sulfogalactosylalkylacylglycerol (SGG), a lipid previously shown to be present primarily in primary spermatocytes, spermatids, and spermatozoa, was enriched 33.1-fold in the plasma membrane fraction; this finding as well as experiments with [35S]sulfate-labeled sulfogalactosylalkylacylglycerol at various times after injection of radioactive label have indicated that both spermatocytes and spermatids were contributing SGG-rich membrane material to our plasma membrane preparation. This membrane material is most probably derived from the plasma membranes of the spermatocytes and spermatids.
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PMID:Enrichment of sulfogalactosylalkylacylglycerol in a plasma membrane fraction from adult rat testis. 745 82

Adenosine triphosphate metabolism in caudal epididymis bovine spermatozoa was studied. Measurements by HPLC at appropriate time intervals of the spermatozoa content of ATP and its derivatives were carried out under different experimental conditions. In the presence of 2-D-glucose, cellular ATP was transformed almost quantitatively into ADP and AMP at a rate of 2.3 nmol/min per 10(8) cells. At the same time, ADP and AMP accumulated at a rate of 1.52 and 0.58 nmol/min per 10(8) cells, respectively. In the first 4 min, about 50% of total ATP was degraded, the AEC of the cells dropped to non-physiological values while the content of other nucleosides did not vary significantly. Inorganic P(i) content also remained unchanged. Under non-induced conditions up to 240 min, no variations of the adenylic content and of the EC value was observed. Under induced and non-induced conditions, IMP and adenosine were not detected within the spermatozoa. The lack of IMP might be ascribed either to the absence of AMP deaminase, whose activity has never been found in the spermatozoa or to the intracellular environment which down regulates the activity of the enzyme. In order to explain low levels and absence of variations of adenosine, several enzymic investigations were carried out. Adenosine kinase activity was not determined, therefore the transformation of adenosine into AMP had to be excluded. Nevertheless, enzymic activities potentially able to dephosphorylate the formed AMP are present in the spermatozoa. Our findings are indicative of the existence in the spermatozoa of acid and alkaline phosphatase and of 5'-nucleotidase membrane-derived.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adenosine triphosphate catabolism in bovine spermatozoa. 758 34

A polyclonal rabbit antibody against 5'-nucleotidase purified from bull seminal plasma was used to localize the antigen on bovine spermatozoa. Spermatozoa taken from the ampulla of the vas deferens showed strong immunofluorescence at the anterior rim of the head portion. Evaluation of spermatozoa prepared from different segments of the seminal pathway indicated the presence of the antigen already in rete testis and epididymal spermatozoa. On cryostat sections of testis tissue a positive immunoreaction was found in the anterior head portion of elongated spermatids, but not in earlier forms of sperm development. This distribution corresponded with the enzyme activity and results of Western blotting in extracts of testicular and epididymal spermatozoa. Immunoelectron microscopy of ampullary spermatozoa using antibody detection with gold-labelled anti-rabbit IgG showed a clear-cut labelling of the plasma membrane in the acrosome region. Treatment of ampullary spermatozoa with 0.1% Triton X-100 did not completely remove the immunoreactive material from the acrosome, showing a very stable linkage of the protein to the plasma membrane. Treatment with phospholipase C from Bacillus thuringiensis, however, removed immunoreactive material from the plasma membrane, indicating its binding by a phosphoinositol anchor. Our findings show that endogenous 5'-nucleotidase is present on the plasma membrane covering the anterior head portion of bovine spermatozoa and indicate specialized functions during the acrosomal reaction. Soluble enzyme derived from seminal vesicle secretion covers the whole sperm surface during emission, but is not covalently bound. It provides generalized enzyme activity to the sperm surface in addition to the specialized area of the sperm head.
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PMID:Distribution of endogenous and exogenous 5'-nucleotidase on bovine spermatozoa. 792 8


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