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PubMed1982

Galatosialidosis (beta-galactosidase-neuraminidase deficiency): clinical and biochemical studies on 13 patients.

Thirteen patients with galactosialidosis (beta-galactosidase-neuraminidase deficiency) from 9 families including two autopsy cases were studied from clinical, genetic, cytological and biochemical standpoints. Coarse facies, myoclonus, cerebellar ataxia, angiokeratoma, loss of vision, corneal opacity and cherry-red spots were the main signs and symptoms although these clinical manifestations were widely variable in individual cases. It is not yet known whether these clinical variations represent genetic heterogeneity or not. Deficiency of beta-galactosidase and neuraminidase was the most prominent biochemical abnormality in this disease. Beta-Galactosidase activity was restored in fibroblasts when serine-thiol protease inhibitors were added to the culture medium. Cathepsin B activity was significantly high in fibroblasts, liver and brain from the patients. It was demonstrated that neuraminidase was susceptible to the procedures for disrupting cells and tissues, such as sonication and freezing. The stability of this enzyme may be dependent on the molecular state in relation to cell membranes.

Adult↗
PubMed1996

Comparison of the canine and human acid beta-galactosidase gene.

Several canine cDNA libraries were screened with human beta-galactosidase cDNA as probe. Seven positive clones were isolated and sequenced yielding a partial (2060 bp) canine beta-galactosidase cDNA with 86% identity to the human beta-galactosidase cDNA. Preliminary analysis of a canine genomic library indicated conservation of exon number and size. Analysis by Northern blotting disclosed a single mRNA of 2.4 kb in fibroblasts and liver from normal dogs and dogs affected with GM1 gangliosidosis. Although incomplete, these results indicate canine GM1 gangliosidosis is a suitable animal model of the human disease and should further efforts to devise a gene therapy strategy for its treatment.

Amino Acid Sequence↗
PubMed1998

Identification of a novel point mutation (S65T) in alpha-galactosidase A gene in Chinese patients with Fabry disease. Mutations in brief no. 169. Online.

Fabry disease is an X-linked inborn error of sphingolipid catabolism resulting from deficient enzyme activity of alpha-galactosidase A. The molecular defects of human alpha-galactosidase A gene causing Fabry disease have been characterized, including gene rearrangement and point mutations, which show the genetic heterogeneity in Fabry disease. To characterize the molecular defects of these patients, each exon of alpha-galactosidase A gene including intron-exon junctions were PCR amplified using biotin-labelled primer and sequenced using magnetic beads solid-phase sequencing. A G to C transversion was identified in the last nucleotide of exon 1 in two unrelated Chinese patients. This mutation obliterates an EcoN1 restriction site. Family studies show close linkage with the affected family members. Screening of 100 alleles (22 males, 39 females) of unrelated normal Chinese can not find this mutation. This mutation not only changes the amino acid from serine to threonine, but also likely cause splicing defects. To our knowledge, this is the first report of mutation in Chinese patients with Fabry disease, and a novel mutation causing Fabry disease not reported in literature previously.

Adult↗
PubMed2003

Production and characterization of alpha-galactosidase from Aspergillus flavipes.

An extracellular alpha-galactosidase from the culture filtrate of Aspergillus flavipes grown on melibiose as a carbon source was partially purified by hydroxylapatite and diethylaminoethylcellulose chromatographies. Electrophoretic analysis showed protein bands corresponding to alpha-galactosidase and invertase activities. The optimum pH and temperature were determined as 4.5-5.0 and 45 degrees C, respectively. The Km value for p-nitrophenyl-alpha-d-galactopyranoside was found to be 1.89 mm. The results reported in this study indicate that Aspergillus flavipes is indeed an active source of extracellular alpha-galactosidase.

Aspergillus↗
PubMed2004

PLA and PLGA microspheres of beta-galactosidase: Effect of formulation factors on protein antigenicity and immunogenicity.

The entrapment of beta-galactosidase (Escherichia coli) in PLA and PLGA microspheres using a double emulsion technique resulted to significant reduction of protein antigenicity. The extent of antigenicity loss depended on the conditions of microsphere preparation. Most of antigenicity loss occurred on the first emulsification step. Only the effects of microsphere preparation factors having an important influence on protein antigenicity, such as the type of organic phase (polymer solvent) and homogenization, could be predicted (on a qualitative basis) by antigenicity data obtained after the first emulsification step. The type of polymer and polymer solvent used to prepare the microspheres affected beta-galactosidase immunogenicity. The PLA microspheres prepared using ethyl acetate was the most immunogenic microsphere formulation, eliciting similar total antibody responses as the alum formulation of beta-gal. This formulation was the only microsphere formulation that induced an IgG1/IgG2a ratio lower than 1, indicating an immune response biased towards a Th1 type. The results obtained indicate that large protein molecules with complex tertiary structure such as beta-galactosidase can be entrapped in PLA and PLGA microspheres with retention of protein immunogenic potential, providing that appropriate conditions of microsphere preparation are applied, and that the formulation of microspheres might influence the Th1/Th2 type of immune response against the encapsulated antigen.

Animals↗
PubMedDate not supplied

An efficient two step purification and molecular characterization of beta-galactosidases from Aspergillus oryzae.

Beta-galactosidases (beta-D-galactoside-galactohydrolases (EC 3.2.1.23), lactases) are important industrial enzymes used for the hydrolysis of lactose from milk and milk whey. These enzymes are produced by different organisms and purified by multi-step procedures. The multi-step purification schemes are cost and time ineffective which can also lead to poor yield, denaturation and loss of enzymatic activity. In our study, extracellular beta-galactosidase from mutant strain Aspergillus oryzaeH26-10-7 was purified by a two step procedure, Metal-ion Affinity Chromatography (IMAC) followed by size-exclusion separation. Purified enzyme was characterized by sodium dodecyl Sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and zymographic analysis. This fungal beta-galactosidase was characterized as a protein corresponding to 113 kDa. Enzyme from mutant strain was found to have five times higher catalytic activity on the synthetic substrate o-nitrophenyl-beta-D-galactopyranoside (ONPG) compared to the wild type enzyme. Moreover, the mutant enzyme was more thermo resistant compared to the wild type. This highly important technological characteristic can be exploited in food industry. Moreover, based on the IMAC patterns of wild type and mutant enzymes, similarities in their His topography were supposed.

Aspergillus oryzae↗
PubMed1996

Influence of the GroE molecular chaperone machine on the in vitro refolding of Escherichia coli beta-galactosidase.

We have studied the effect of the components of the GroE molecular chaperone machine on the refolding of the Escherichia coli enzyme beta-galactosidase, a tetrameric protein whose 116-kDa promoters should not completely fit within the central cavity of the GroEL toroid. In the absence of other additives, GroEL formed a weak complex with chemically denatured beta-galactosidase, reduced its propensity to aggregate, and increased the recovery yields of active enzyme twofold without altering its folding pathway. When present together with the chaperonin, ATP--and to a lesser extent AMP-PNP--reduced the recovery yields and led to the resumption of aggregation. The use of the complete chaperonin system (GroEL, GroES, and ATP) eliminated the GroEL-mediated increase in recovery and folding proceeded less efficiently than in buffer alone. This unusual behavior can be explained in terms of a chaperonin "buffering" effect and the different affinities of GroE complexes for denatured beta-galactosidase.

Adenosine Triphosphate↗
PubMed2004

Probing the alpha-complementing domain of E. coli beta-galactosidase with use of an insertional pentapeptide mutagenesis strategy based on Mu in vitro DNA transposition.

Protein structure-function relationships can be studied by using linker insertion mutagenesis, which efficiently identifies essential regions in target proteins. Bacteriophage Mu in vitro DNA transposition was used to generate an extensive library of pentapeptide insertion mutants within the alpha-complementing domain 1 of Escherichia coli beta-galactosidase, yielding mutants at 100% efficiency. Each mutant contained an accurate 15-bp insertion that translated to five additional amino acids within the protein, and the insertions were distributed essentially randomly along the target sequence. Individual mutants (alpha-donors) were analyzed for their ability to restore (by alpha-complementation) beta-galactosidase activity of the M15 deletion mutant (alpha-acceptor), and the data were correlated to the structure of the beta-galactosidase tetramer. Most of the insertions were well tolerated, including many of those disrupting secondary structural elements even within the protein's interior. Nevertheless, certain sites were sensitive to mutations, indicating both known and previously unknown regions of functional importance. Inhibitory insertions within the N-terminus and loop regions most likely influenced protein tetramerization via direct local effects on protein-protein interactions. Within the domain 1 core, the insertions probably caused either lateral shifting of the polypeptide chain toward the protein's exterior or produced more pronounced structural distortions. Six percent of the mutant proteins exhibited temperature sensitivity, in general suggesting the method's usefulness for generation of conditional phenotypes. The method should be applicable to any cloned protein-encoding gene.

Amino Acid Sequence↗
PubMed1997

Measure of transient transfection efficiency using beta-galactosidase protein.

Although the control elements which regulate the transcriptional activity of promoter sequences are largely determined by the use of reporter plasmids in transient transfection analyses, controlling variability in these experiments can often be a vexing problem. Problems arise when the promoter of the internal control plasmid, used to correct for transfection efficiency, either affects test promoter strength or is itself regulated by trans-acting factors or inducing agents used to study the test promoter. Here we report the use of beta-galactosidase protein as an unbiased standard of transfection efficiency. beta-Galactosidase protein is readily internalized by adherent cell lines when incorporated into a calcium phosphate precipitate; significant enzyme activity can be recovered up to 72 h after transfection. Use of beta-galactosidase protein as a control obviates the concerns associated with promoter-dependent reporter plasmids as controls.

Calcium Phosphates↗
PubMed1999

Fluorogenic substrates based on fluorinated umbelliferones for continuous assays of phosphatases and beta-galactosidases.

Fluorogenic substrates based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase and glycosidase activities. One disadvantage of these substrates, however, is that maximum fluorescence of the reaction product requires an alkaline pH, since 4-MU has a pK(a) approximately 8. In an initial screening of five phosphatase substrates based on fluorinated derivatives of 4-MU, all with pK(a) values lower than that of 4-MU, we found that one substrate, 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP), was much improved for the detection of acid phosphatase activity. When measured at the preferred acid phosphatase reaction pH (5.0), DiFMUP yielded fluorescence signals that were more than 10-fold higher than those of 4-methylumbelliferyl phosphate (MUP). DiFMUP was also superior to MUP for the detection of protein phosphatase 1 activity at pH 7 and was just as sensitive as MUP for the detection of alkaline phosphatase activity at pH 10. A beta-galactosidase substrate was also prepared based on 6, 8-difluoro-4-methylumbelliferone. This substrate, 6, 8-difluoro-4-methylumbelliferyl beta-d-galactopyranoside (DiFMUG), was found to be considerably more sensitive than the commonly used substrate 4-methylumbelliferyl beta-d-galactopyranoside (MUG), for the detection of beta-galactosidase activity at pH 7. DiFMUP and DiFMUG should have great utility for the continuous assay of phosphatase and beta-galactosidase activity, respectively, at neutral and acid pH.

Acid Phosphatase↗
PubMed1994

Two histidines are essential for the activity of the beta-galactosidase from Lactobacillus delbrückii subsp. bulgaricus.

Twelve tyrosines, ten glutamates, and five histidines were individually substituted for phenylalanine, glutamine, and asparagine, respectively, in the beta-galactosidase from Lactobacillus delbrückii subsp. bulgaricus. Only Y509, E464, H351, and H534 appear to be essential for the activity of the enzyme. The residues Y509 and E464 are homologous to Y503 and E461, respectively, of the Escherichia coli lacZ beta-galactosidase which have been shown to be necessary for its activity. Surprisingly, a number of amino acids that are highly conserved in the sequence alignments of nine beta-galactosidases and four beta-glucuronidases are not essential for enzyme activity.

Amino Acid Sequence↗
PubMed1995

Apoc-III-beta-galactosidase hybrid distinguishes between VLDL and LDL phospholipids.

A plasmid directing the expression of preapolipoprotein C-III fused to beta-galactosidase was constructed. Escherichia coli harboring this construct produced the hybrid, with full beta-galactosidase activity, at 0.6% of total cellular protein. Purified preapoC-III-beta-galactosidase hybrid exhibited specific binding to very low density lipoproteins, which was inhibited by purified apoC-III. No binding to low density lipoproteins was observed. Binding was mediated by the phospholipids of very low density lipoproteins, as the hybrid had a specific affinity for phospholipids and no detectable affinity for triglycerides, cholesteryl esters, or cholesterol. The differential binding suggests that there are differences between the phospholipids of very low density lipoproteins and the phospholipids of low density lipoproteins.

Amino Acid Sequence↗
PubMed1995

Intracellular stability of alpha fragments of beta-galactosidase: effects of amino-terminally fused polypeptides.

Intracellular stability of alpha fragments of beta-galactosidase in Escherichia coli has been studied by pulse-chase/immunoprecipitation experiments. An alpha fragment encoded by the pUC118 vector was relatively stable with an estimated half-life of about 12 min at 37 degrees C, whereas another vector, pSTV28, encoded a less stable alpha fragment that had a different carboxy-terminal sequence. Stability of the fragment was found to be affected markedly by amino-terminal attachment of other sequences. An amino-terminal fusion of a sequence derived from cytoplasmic domain 4 of the SecY protein shortened the half-life of the alpha fragment to less than 1 min. In contrast, an amino-terminal sequence from the NusG protein had no apparent effect on the stability of the fragment. In a fusion protein in which the intact SecY protein was fused to the alpha fragment, stabilization of the SecY part by overproduction of the partner SecE protein resulted in an increased alpha complementation activity of beta-galactosidase. These results indicate that stability of alpha fragment can be dictated by the stability of the fused protein. The alpha fragment of beta-galactosidase, which is unique in that it is largely unstructured but can be "active" in alpha complementation, may be used as an in vivo indicator of stability of proteins attached to it.

Amino Acid Sequence↗
PubMed2002

Measuring beta-galactosidase activity in bacteria: cell growth, permeabilization, and enzyme assays in 96-well arrays.

We describe a high-throughput procedure for measuring beta-galactosidase activity in bacteria. This procedure is unique because all manipulations, including bacterial growth and cell permeabilization, are performed in a 96-well format. Cells are permeabilized by chloroform/SDS treatment directly in the 96-well blocks and then transferred to 96-well microplates for standard colorimetric assay of beta-galactosidase activity as described by Miller [J. H. Miller (1972) Experiments in Molecular Genetics, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY]. Absorbance data are collected with a microplate reader and analyzed using a Microsoft Excel spreadsheet. The beta-galactosidase specific activity values obtained with the high-throughput procedure are identical to those obtained by the traditional single-tube method of Miller. Thus, values obtained with this procedure may be expressed as Miller units and compared directly to Miller units reported in the literature. The 96-well format for permeabilization and assay of enzyme specific activity together with the use of 12-channel and repeater pipettors enables efficient processing of hundreds of samples in an 8-h day.

Bacteria↗
PubMed2001

Effect of an E461G mutation of beta-galactosidase (Escherichia coli, lac Z) on pL rate profiles and solvent deuterium isotope effects.

An E461G mutation of beta-galactosidase results in the disappearance of the high pL (L = H, D) downward break in the rate profiles for k(cat)/K(m) for wild-type enzyme-catalyzed hydrolysis of 4-nitrophenyl beta-D-galactopyranoside (Gal-OPNP) and a decrease from (k(cat))(HOH)/(k(cat))(DOD) = 1.7 to (k(cat))(HOH)/(k(cat))(DOD) = 1.2 in the solvent deuterium isotope effect. These observations provide evidence that the propionic acid side chain of Glu 461 is protonated at catalytically active free beta-galactosidase and they are consistent with a role for this residue in Brønsted acid catalysis at the leaving group. The earlier observation that this same E461G mutation results in the loss of a downward break at high pH in the rate profile for k(s) for transfer of the beta-D-galactopyranosyl group from beta-galactosidase to water cannot be simply explained by a mechanism in which the single side chain of Glu 461 functions to provide general acid catalysis in the rate limiting step for formation of the beta-D-galactopyranosyl intermediate and general base catalysis of breakdown of this intermediate. Evidence is presented that there may be different catalytic mechanisms, with different roles for the side chain for Glu-461, for nucleophilic addition of water and of small alkyl alcohols to the beta-D-galactopyranosyl reaction intermediate.

Deuterium↗
PubMed2000

Rat spermatogenic cell beta-D-galactosidase: characterization, biosynthesis, and immunolocalization.

In this study we have demonstrated that the rat sperm acrosomal beta-d-galactosidase is expressed in late spermatocytes and spermatids (round, elongated/condensed) during spermatogenesis. The enzyme is an exoglycohydrolase which, along with other exoglycohydrolases and proteases, is thought to aid in penetration of the zona pellucida, the extracellular glycocalyx that surrounds the mammalian egg. The presence of the enzyme in spermatocytes was confirmed by multiple approaches using biochemical, biosynthetic, and immunohistochemical protocols. The germ cells (spermatocytes, round spermatids, and elongated/condensed spermatids), purified from rat testis, were found to contain beta-galactosidase and four other glycohydrolases (beta-d-glucuronidase, alpha-d-mannosidase, alpha-l-fucosidase, and beta-N-acetylglucosaminidase). With the exception of alpha-l-fucosidase, the other enzymes assayed demonstrated a two- to threefold higher activity per cell in spermatocytes than in round spermatids. Immunoblotting approaches of affinity-purified germ cell extracts demonstrated several molecular forms of beta-galactosidase in spermatocytes and round spermatids; one of these forms (62 kDa) was seen only in round spermatids. The biosynthetic approach demonstrated that the enzyme is synthesized in spermatocytes and round spermatids in culture in high-molecular-weight precursor forms (90/88 kDa) which undergo processing to lower molecular weight mature forms in a cell-specific manner. The net result is the formation of predominantly 64- and 62-kDa forms in spermatocytes and round spermatids, respectively. The conversion of precursor forms to mature forms in the diploid and haploid cells in culture is rapid with t(1/2) of 6.5 and 9.0 h, respectively. Immunohistochemical approaches revealed an immunopositive reaction in the Golgi membranes, Golgi-associated vesicles, and lysosome-like structures in the late spermatocytes and early round spermatids. The forming/formed acrosome in round and elongated spermatids was also immunoreactive.

Acetylglucosaminidase↗
PubMed1998

Murine alpha-N-acetylgalactosaminidase: isolation and expression of a full-length cDNA and genomic organization: further evidence of an alpha-galactosidase gene family.

Recent characterization of the human sequences encoding two lysosomal hydrolases, alpha-galactosidase A (alpha-Gal A) and alpha-N-acetylgalactosaminidase (alpha-GalNAc) revealed that these two enzymes with distinct enzymatic activities shared about 50% overall amino acid identity and that their genomic sequences had a conserved common gene structure. These findings suggested that these genes, which are located on different chromosomes, arose by duplication and divergence from a common ancestral gene. To further compare this alpha-galactosidase gene family, the murine alpha-GalNAc cDNA and genomic sequences were isolated and characterized. The full-length cDNA contained an open-reading frame of 1245 bp encoding a 415 amino acid polypeptide and had 5' and 3' untranslated regions of 94 and 333 bp, respectively. The coding region had 81% nucleotide and 81.9% amino acid identities with those of the corresponding human alpha-GalNAc sequence. Northern analysis revealed a single transcript of approximately 1.9 kb. The functional integrity of the cDNA was demonstrated by transient expression in COS-1 cells. The murine alpha-GalNAc genomic sequence spanned approximately 9 kb and was identical in structure with the human alpha-GalNAc gene with eight introns interrupting the coding sequence at identical positions. In addition, the deduced amino acid sequence of the murine alpha-GalNAc gene was highly homologous with alpha-GalNAc and alpha-Gal A genes from other species providing further support for a common evolutionary ancestor of the alpha-galactosidase gene family. The availability of the murine gene will permit additional evolutionary comparisons, structure/function analyses, and the generation of mice with alpha-GalNAc deficiency by gene targeting.

Amino Acid Sequence↗
PubMed1989

Cloning and nucleotide sequence of the alpha-galactosidase cDNA from Cyamopsis tetragonoloba (guar).

Polyadenylated mRNA was purified from the aleurone cells of Cyamopsis tetragonoloba (guar) seeds germinated for 18 h and used for the construction of a cDNA library. Clones with the alpha-galactosidase encoding gene were identified using oligo-nucleotide mixed probes based on the NH2 terminal amino acid sequence and on the sequence of an internal peptide. The nucleotide sequence of the cDNA clone showed that the enzyme is synthesized as a precursor with a 47 amino acid NH2 terminal extension. This pre-sequence most likely functions to target the protein outside the aleurone cells into the endosperm. Based upon structural features, it is proposed to divide the precursor into a pre-(signal sequence) part and a glycosylated pro-part comparable with those of the yeast mat A/alpha factor and killer factor. A comparison of the derived amino acid sequence of this alpha-galactosidase from plant origin revealed significant stretches of homology with respect to the amino acid sequences of the enzymes from Saccharomyces cerevisiae and from human origin but only to a minor extent compared with the alpha-galactosidase from Escherichia coli.

Amino Acid Sequence↗