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:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Streptozotocin treatment (125 mg/kg) in the Chinese hamster induced hyperglycaemia, hypoinsulinaemia, hyperglucagonaemia and changes in body, liver, pancreas, stomach, kidney and adipose tissue weights. The pancreatic reserves of insulin and glucagon in the diabetic animals were low, but stomach glucagon high. These animals showed high levels of phosphoenolpyruvate carboxykinase and low levels of glucokinase, hexokinase, isocitrate dehydrogenase and malic enzyme, but normal levels of pyruvate kinase in the liver. Increases in lactate dehydrogenase subunit B and isozymes 2, 3 and 4 were also observed in the liver, but not in the epididymal fat pad, of the diabetic animals. N-Acetyl-beta-D-glucosaminidase was elevated in plasma, liver and heart, but not in the kidney of the treated animals. Renal alpha-galactosidase and beta-glucosidase were depressed, whereas beta-galactosidase and alpha-glucosidase remained essentially normal. These features indicated that there were considerable differences between the biochemical disorders associated with streptozotocin-diabetes in the Chinese hamster and the published observations in the rat.
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PMID:Streptozotocin-induced diabetes in the Chinese hamster. Biochemical and endocrine disorders. 59 Jun 51

Impact of altered serum prolactin status on enzymes involved in glycoprotein metabolism in epididymal tissue of matured monkeys was studied. Hyperprolactinemia (ovine prolactin-250 micrograms/kg body weight/day for 30 days) significantly inhibited the specific activities of dolichylphosphate mannosyl transferase, dolichylphosphate glucosyl transferase and galactosyl transferase, in the epididymal tissues. However, it had an enhanced effect on epididymal glycosidases such as beta-galactosidase, beta-N-acetyl glucosaminidase, beta-N-acetyl galactosaminidase, alpha-mannosidase and alpha-L-fucosidase. Hypoprolactinemia (bromocriptine mesylate-1-mg/kg body weight/day for 30 days) on other hand had no significant effect on the specific activities of both, glycosyltransferases and glycosidases, in the epididymal tissues. The results suggest that hyperprolactinemia inhibits epididymal glycoprotein metabolism by impairing the incorporation of oligosaccharide units into proteins with enhanced degradation. This may have adverse effect on events leading to sperm maturation in epididymal environment.
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PMID:Role of prolactin on epididymal glycoprotein metabolism in matured monkeys, Macaca radiata: specific activities of glycosyltransferases and glycosidases. 129 32

Alterations to the mammalian genome that occur during the development of germ cells, in particular during meiosis, can be introduced into the population upon fertilization. These alterations can occur through homologous recombination, genome rearrangement, or mutagenesis. Such events usually occur infrequently for any particular sequence. Because of the difficulty in analyzing a large number of offspring in a mammalian cross, we have developed a marker to detect these events in sperm, since a large number of these meiotic progeny are produced during male gametogenesis. We have expressed the Escherichia coli lacZ gene during spermatogenesis in transgenic mice and quantitated the levels of beta-galactosidase activity in single sperm with the fluorescence-activated cell sorter and a fluorogenic substrate, 5-dodecanoylaminofluorescein di-beta-D-galactopyranoside. Detection of rare positives was demonstrated in mixed sperm populations with as few as 0.01% positive sperm. Although the distribution of beta-galactosidase activity in caudal epididymal sperm populations is bimodal, it appears that beta-galactosidase, like other proteins that have been expressed postmeiotically, is distributed between transgene-positive and transgene-negative sperm.
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PMID:Analysis of Escherichia coli beta-galactosidase expression in transgenic mice by flow cytometry of sperm. 143 65

beta-Galactosidase, known to be secreted by epithelial cells lining the rat epididymal duct, binds to the surface of spermatozoa from the caudal region with high affinity and in a saturable form. The binding was not inhibited by mannose-6-phosphate, but was inhibited by fructose phosphate derivatives, a peculiarity previously demonstrated for the membranes of epididymal tissue. Fructose phosphate derivatives released 55% of beta-galactosidase activity from the spermatozoa. These results suggest that in the epididymis there is a special transport system for hydrolases, which could be involved in the secretion of enzymes destined for spermatozoa. This transport would require receptors that recognize sugar ligands other than mannose-6-phosphate. These receptors were present in the epididymal tissue and on the sperm surface.
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PMID:Binding of beta-galactosidase from rat epididymal fluid to the sperm surface by high-affinity sites different from phosphomannosyl receptors. 178 47

Fluid of rat cauda epididymidis was obtained by flushing the duct with 0.25 mol l-1 sucrose in 0.01 mol l-1 Tris-HCl buffer pH 7.4. The fluid was centrifuged at 600 x g for 15 min and the sperm free supernatant was centrifuged at 47,000 x g for 1 h. The sediments observed with the electron microscope consisted of a heterogeneous population of membrane-bound vesicles similar to those seen in the intact organ. In the sediment containing the vesicles the activity of beta-galactosidase was mostly unavailable for the substrate showing a high degree of latency: the activity became soluble after a treatment with 0.5% saponin. The activity of N-acetyl-galactosaminadase instead, was mainly available for the substrate and soluble in buffer containing 0.6 mol l-1 KCl. It was then inferred that beta-galactosidase is located inside vesicles with no or little affinity for the membrane, while N-acetylglucosaminadase is bound to the external surface of vesicles. Supernatants and precipitates from suspensions of vesicles in buffered 0.5% saponin were analysed for proteins by gel electrophoresis. The electrophoretic patterns of the sediments were very different from those of supernatants and showed a number of bands greater than that of the latter. The vesicles are believed to arise from the epididymal epithelium, but their physiological role is unknown.
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PMID:First observations on enzymatic activity and protein content of vesicles separated from rat epididymal fluid. 180 9

Gamma-Glutamyl transpeptidase (gamma-GT) was studied histochemically and biochemically in the rat epididymis after castration with or without testosterone treatment, or after hemicastration and ligation of the efferent ducts. There was a strong reaction to gamma-GT in the apical part of the epithelium in the caput epididymis, while in the corpus and cauda the reaction was confined mainly to the luminal contents. Castration caused a marked decline in epithelial gamma-GT activity within 10 days. Subsequent testosterone treatment (1 mg/day for 10 days) restored gamma-GT activity in the apical surface and lumen. After hemicastration of adult rats, and after hemicastration or ligation of the efferent ducts in immature 28-day-old rats, a small but significant (P less than 0.001) decrease was observed in gamma-GT activity in the epididymal caput compared to controls. The quantities of six other enzymes (beta-N-acetylglucosaminidase, beta-galactosidase, angiotensin-converting enzyme, alanyl amino-peptidase, dipeptidyl peptidase IV, acid phosphatase) also displayed significant changes after castration and restoration of activities by testosterone treatment. However, their distribution in the caput and cauda epididymis was more even than that of gamma-GT, and the changes after castration were less drastic. It is concluded that gamma-GT is a highly sensitive androgen-dependent secretory marker in the caput epididymis and may have an important function in sperm maturation.
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PMID:Gamma-glutamyl transpeptidase in rat epididymis: effects of castration, hemicastration and efferent duct ligation. 257 65

In order to know if the beta-galactosidase of the rat epididymal fluid, as other secreted acid hydrolases, carries a marker in its molecule, we studied the binding of this enzyme to cellular membranes of the epididymal tissue. The binding, like that mediated by the phosphomannosyl receptor, was saturable, did not require calcium, had a Kd in the nM range and was inhibited by phosphatase or metaperiodate treatment of the enzyme. However fructose 6-phosphate derivates were more effective competitive inhibitors than mannose 6-phosphate. The binding capacity of the membranes were extractable with Triton X-100 and incorporable into liposomes. Trypsin inhibited the binding capacity of Triton extracts but it did not affect the affinity of intact cellular membranes for beta-galactosidase. The results suggest that a phosphorylated carbohydrate of the enzyme is bound by a recognizing site of the cellular membranes different from the phosphomannosyl receptor.
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PMID:beta-Galactosidase from rat epididymal fluid is bound by a recognition site attached to membranes of the epididymis different from the phosphomannosyl receptor. 303 84

During transit through the epididymis, spermatozoa acquire fertilizing the cell surface exhibits an altered glycoprotein pattern. Epididymal cells and their secretions contribute to these sperm-surface changes. To examine this process, epithelial cells from rat caput and cauda epididymidis were cultured and examined for the synthesis, processing and secretion of two glycoprotein-modifying enzymes, beta-galactosidase and beta-glucuronidase. Cells were cultured four days, incubated with D-2-[3H] mannose and L-[35S] methionine, and placed in isotope-free media. Levels of both cellular and secreted beta-galactosidase and beta-glucuronidase were determined by immunoprecipitation of cell homogenates or medium, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and scintillation counting of bands. During a 1-h pulse, both caput and cauda cells synthesize two precursor forms of beta-galactosidase (Mr = 84,000 and 87,000), which are processed to the mature (Mr = 63,000) enzyme during a 24-h chase. Caput cells release a high molecular weight (HMW) form (Mr = 90-100,000) and mature beta-galactosidase into the media, but not the Mr = 84-87,000 precursor. On the other hand, cauda cells release mostly mature beta-galactosidase. Ratios of radiolabeled mannose/methionine demonstrate a 7-fold greater mannose content in the cellular precursor of beta-galactosidase than in total protein. Another glycosidase, beta-glucuronidase, is synthesized as a Mr = 78,000-precursor which is processed to the mature Mr = 72,000 form. Medium in which caput and cauda cells were cultured contains both mature enzyme and a Mr = 94,000 form, but no 78,000-precursor form. Ratios of radiolabeled mannose/methionine in the cellular precursor of beta-glucuronidase are 2-fold greater than ratios in the total glycoprotein. Secretion is the major pathway of turnover for several epididymal glycosidases, since more than 50% of the total is secreted/day. These results indicate that cultured epithelial cells from the epididymis synthesize glycosidases and that processing and release differ, depending on the enzyme and the epididymal segment from which the epithelial cells were isolated.
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PMID:Glycosidases in cultured rat epididymal cells: enzyme activity, synthesis and secretion. 309 Nov 1

The distribution of beta-galactosidase activity was studied in different reproductive organs, seminal plasma and spermatozoa of the bull. The highest specific activity of beta-galactosidase was found in testis and in different parts of the epididymis, where the activity seemed to be partly in secretory (cauda secretion) and partly in non-secretory, bound form (caput to cauda epididymidis). Gel filtration on Sepharose 6B at pH 7.0 revealed two beta-galactosidase forms (GF-1, Mr approximately 500,000-600,000 and GF-2, Mr approximately 190,000-220,000) in reproductive organs and seminal plasma. The pH-optimum of both beta-galactosidase forms was about 3.75-4.75. Hg2+ and p-chloromercuribenzoate inhibited strongly these activities. Further, form GF-2 seemed to be slightly more sensitive to the thermal inactivation at 50-70 degrees C than form GF-1. In chromatofocusing beta-galactosidase activities in bull seminal plasma coeluted with those of the cauda epididymidis (pI-values 7.5-6.4). On the contrary, prostate, Cowper's gland, testis, ampulla and seminal vesicles had enzyme activities eluting at lower pI-values (6.3-4.2). Thus, the seminal plasma activity is mainly an indicator for the function of the epididymal cauda.
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PMID:Beta-galactosidase in the seminal plasma and reproductive organs of the bull. 309 20

Seven glycosidases (beta-N-acetylglucosaminidase, alpha-fucosidase, beta-galactosidase, acid alpha-glucosidase, beta-glucuronidase, acid and neutral alpha-mannosidase) were analysed in seminal plasma from the first and second successive ejaculates in normal Ayrshire bulls. In comparison to our previous data the results indicate that beta-N-acetylglucosaminidase, beta-galactosidase and beta-glucuronidase are derived mainly from epididymal secretions, while alpha-fucosidase and particularly neutral alpha-mannosidase originate additionally from the spermatozoan cytoplasmic droplets. The seminal vesicles appear to contribute particularly to the seminal plasma acid alpha-glucosidase and acid alpha-mannosidase activities. The seminal plasma enzymes derived from the epididymis and cytoplasmic droplets were suppressed in semen samples with low sperm density or with high numbers of abnormal spermatozoa. The epididymal and seminal vesicle enzymes could be utilized in assessment of the secretory/functional capacity of these glands.
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PMID:Comparison of glycosidase levels in bovine seminal plasma. 311 30


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