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:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A major secretory protein of the human epididymis that is taken up by maturing spermatozoa is homologous to the leukocyte antigen CD52. The epididymis was shown to be the sole source of CD52 in seminal fluid, since CD52 could be detected in seminal plasma from sperm-containing ejaculates and not in ejaculates of vasectomized patients by Western blot analysis. The glycoprotein is not expressed in the testes. A fluorescence immunobinding assay was developed to quantify the amount of epididymal secretion of CD52 in the seminal plasma of various groups of fertile and infertile patients. Donor spermatozoa bearing CD52 were used as binding site tracers for free anti-CD52 antibody remaining after it had adsorbed CD52 from the seminal plasma to be assayed. The level of subsequent antibody binding to spermatozoa was measured by flow cytometry and the extent of binding inhibition was compared to a reference pool of seminal plasma to provide relative amounts of CD52 in test seminal plasma. There were no correlations between seminal plasma CD52 concentration and any semen parameter tested, including sperm concentration, percentage motility, normal sperm morphology or the concentration of seminal neutral alpha-glucosidase, fructose and zinc. There was a slight tendency towards an inverse relationship with the amount of CD52 on spermatozoa, but this was not significant. No differences were found among groups of patients classified by their semen parameters or fertility status. These findings indicate that the epididymal specific supply of CD52 is not a limiting factor for CD52 uptake onto spermatozoa.
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PMID:Epididymal secretion of CD52 as measured in human seminal plasma by a fluorescence immunoassay. 966 31

A gene, designated amyR, coding for a transcriptional activator involved in amylolytic gene expression has been cloned from Aspergillus oryzae by screening for a clone that enabled to reverse the reduced expression of the alpha-amylase gene (amyB) promoter. amyR encodes 604 amino acid residues of a putative DNA-binding protein carrying a zinc binuclear cluster motif (Zn(II)2Cys6) belonging to the GAL4 family of transcription factors. The amyR gene disruptants showed a significant restricted growth on starch medium and produced little of the amylolytic enzymes including alpha-amylase and glucoamylase compared with a non-disruptant, indicating that amyR is a transcriptional activator gene involved in starch/maltose-induced efficient expression of the amylolytic genes in A. oryzae. In addition, sequencing analysis found that amyR, agdA (encoding alpha-glucosidase), and amyA (encoding alpha-amylase), are clustered on a 12-kb DNA fragment of the largest chromosome in A. oryzae, and that amyR is about 1.5 kb upstream of agdA and transcribed in the opposite direction. Furthermore, transcriptional analysis revealed that the amyR gene was expressed in the presence of glucose comparable to the level in the presence of maltose, while the amylolytic genes were transcribed at high levels only in the presence of maltose.
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PMID:Molecular cloning and characterization of a transcriptional activator gene, amyR, involved in the amylolytic gene expression in Aspergillus oryzae. 1083 Apr 98

The clinical value of biochemical analysis of sperm is still unclear. In this study, we evaluated the potential of several biochemical markers in the seminal plasma (zinc, citrate, acid phosphatase, fructose and neutral alpha-glucosidase) as a screening method in male infertility investigation.
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PMID:Biochemical analysis of the sperm and infertility. 1143 97

Seminal viscopathy was shown to be associated with male infertility. However, our knowledge about the regulatory mechanism of this process is still limited. In semen samples from 411 men attending for fertility assessment, traditional semen parameters including visco-elasticity were assessed according to the World Health Organization guidelines. Sperm motility was evaluated by use of computer aided sperm analysis (CASA). Seminal activity of neutral alpha-glucosidase (NAG) and concentrations of prostate-specific antigen (PSA), zinc, and fructose were measured. The activity of NAG, and the concentrations of PSA and zinc were significantly lower in hyper-visco-elastic semen samples (medians: 5 vs. 8 mU/mL; 741 vs. 924 mg/L; 1 vs. 2 mM/L), than in those with normal visco-elasticity (p = 0.004, 0.005 and 0.011, respectively). When comparing the total amounts, only for seminal fructose there was a difference between samples with high visco-elasticity as compared with those of normal visco-elasticity (median: 74 vs. 53 microM/ejaculate, p = 0.007) This seminal marker was the only significant independent parameter in predicting seminal visco-elasticity in a multiple logistic regression analysis (odds ratio for the highest quartile = 4.67). Hyper-visco-elasticity was associated with a lower percentage of motile spermatozoa (43 vs. 50%, p = 0.045). Similar trend was found for the CASA motility characteristics curvilinear velocity (VCL), average path length (VAP), amplitude of lateral head displacement (ALH) (p = 0.008, 0.038 and 0.020, respectively). Our study demonstrated the interplay between the regulatory effect of post-testicular organs on semen visco-elasticity. Hyper-visco-elasticity was associated with asthenozoospermia and lower levels of VCL, VAP and ALH.
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PMID:Visco-elasticity of seminal fluid in relation to the epididymal and accessory sex gland function and its impact on sperm motility. 1514 67

Inhibition of metal ions and synergetic inhibition of metal ions/genistein on alpha-glucosidase activity has been investigated. We have examined the inhibitory effect of Cu2+, Ni2+, Mg2+, Fe2+, Hg2+, Zn2+, Ca2+, Pb2+, Ag+, V5+, V4+ and Mn2+ ions. The results show that the nature of the inhibition was reversible, slow-binding, non-competitive, and the Ki values of some ions such as Cu2+, Ni2+ and Zn2+ range from 10(-5) to 10(-6) M. Moreover, synergetic inhibitory effect of metal ions and genistein on alpha-glucosidase were studied with kinetics method. It is concluded that the inhibitory effect was much greater when both of them were added to the reactant solution simultaneously than that they were added, respectively, which suggests that the inhibitors seem to bind to the different sites of alpha-glucosidase at the same time. Furthermore, the mechanism of the synergetic inhibition was examined by spectrophotometry.
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PMID:Synergetic inhibition of metal ions and genistein on alpha-glucosidase. 1547 8

We found alpha-glucosidase inhibitory effect of Zn(II) complex with 6-methyl-2-picolinmethylamide (6mpa-ma) which showed the highest blood glucose lowering effect in Zn(II) complexes with picolinamide derivatives in KK-A(y) mice. The Zn(II) complex showed strong alpha-glucosidase inhibitory activity greater by about eighty times (substrate: maltose) and forty times (substrate: sucrose) compared with acarbose.
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PMID:In vitro alpha-glucosidase inhibitory effect of Zn(II) complex with 6-methyl-2-picolinmethylamide. 1580 52

Androgens, including 5alpha-dihydrotestosterone (DHT), are known to play a role for spermatogenesis and accessory sex gland function. The enzyme 5alpha-reductase (SRD5A) catalyses the conversion of testosterone to DHT. Our objective was to investigate whether polymorphisms in the SRD5A2 gene influence semen parameters in the general population. DNA from 182 Swedish military conscripts was examined for the A49T, V89L, and R227Q polymorphisms in the SRD5A type 2 gene. Ejaculates were analysed according to WHO guidelines. In addition, sperm motility was assessed using computer-aided sperm analysis (CASA). Seminal markers of epididymal (neutral alpha-glucosidase), prostatic (prostate specific-antigen and zinc), and seminal vesicles function (fructose) were measured. The A49TT-allele was associated with significantly higher sperm concentration compared with the wild type A-allele (mean: 102 x 10(6)/mL vs. 57 x 10(6)/mL, p = 0.02). The V89LV-genotype was correlated with significantly higher proportion progressive motile spermatozoa compared with the L-variant (mean: 55% vs. 48%, p = 0.04). The same trend was found regarding the CASA motile spermatozoa (mean: 52% vs. 41%, p = 0.02). No association between any of the polymorphisms and biochemical markers was found. SRD5A2 gene variants were associated with sperm concentration and motility, but not with epididymal and accessory sex gland markers. This effect on sperm parameters might therefore be exerted via a direct effect of DHT on spermatogenesis.
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PMID:Significant impact of 5alpha-reductase type 2 polymorphisms on sperm concentration and motility. 1648 6

Summary Prostasomes are prostate-derived organelles in seminal plasma exhibiting pluripotent properties to facilitate the fertilization process. Seminal prostasome concentration, size distribution and expression of the prostasomal surface antigens CD10, CD13, CD26 and CD59 were examined by flow cytometry. The study group consisted of 79 men with involuntary infertility. Very strong correlations existed between the prostasome expressions of the different CD markers. Significant correlations between prostasome concentration and CD molecules were weak or lacking. Further, no or weak relationships were observed between the prostasomal CD markers and sperm morphology, seminal fructose, neutral alpha-glucosidase activity, zinc and tumour necrosis factor alpha concentrations. Flow cytometry is a practical way to study prostasomes in seminal fluid without prior separation. This is a new technique for evaluation of the role of prostasomes and their functions in male reproductive physiology.
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PMID:Flow cytometric technique for determination of prostasomal quantity, size and expression of CD10, CD13, CD26 and CD59 in human seminal plasma. 1653 55

This study was conducted to examine the relationship between the concentration of zinc and neutral alpha-glucosidase (NAG) with semen quality. Semen samples from 75 male partners of couples who were attending the Obstetrics and Gynecology Department were analyzed for semen quality. Based on sperm count, the subjects were divided into three groups. Zinc and neutral alpha-glucosidase activity were estimated in seminal plasma. Results showed that mean the alpha-glucosidase activity was lowest among the azoospermic group with respect to oligozoospermic and normozoospermic groups. Mean zinc levels were also lower among azoospermics compared to oligozoospermic and normospermic groups. The difference was statistically significant (p < 0.05). A significant positive correlation was observed between zinc levels and sperm count (r = 0.29, p < 0.05) and zinc and alpha-glucosidase activity (r = 0.31, p < 0.05) in seminal plasma. These results suggest that zinc and neutral alpha-glucosidase seem to play an important role in human reproduction.
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PMID:Seminal plasma zinc concentration and alpha-glucosidase activity with respect to semen quality. 1675 39

Aspergillus nidulans possessed 16 putative amylolytic genes consisting of 7 alpha-glucosidase (agdA-F), 7 alpha-amylase (amyA-F), and 2 glucoamylase (glaA and B) genes on the genome. Among them, the agdA, agdB, agdE, agdF, amyA, amyB, amyF, and glaB genes were induced by isomaltose. AmyR, a Zn(II)(2)Cys(6) transcription factor, was required for the induction. The isomaltose-inducible genes possessed at least one consensus sequence for AmyR binding, 5'-CGGN(8)CGG, on each promoter region. None of the amylolytic genes was induced by maltose. The mRNA levels of the amylolytic genes except for agdC, amyD, and amyG increased under carbon-starved conditions. Release from CreA-dependent carbon catabolite repression was the main cause of the increase, but, the mRNA levels of agdB, agdF, amyB, amyF, and glaB increased to some extent even in a creA mutant. Therefore, both CreA-dependent and -independent mechanisms are involved in the up-regulation of the amylolytic genes under carbon-starved conditions.
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PMID:Expression profile of amylolytic genes in Aspergillus nidulans. 1703 Oct 28


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