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PubMed1998

alpha1,3 Fucosyltransferase, alpha-L-fucosidase, alpha-D-galactosidase, beta-D-galactosidase, and Le(x) glycoconjugates in developing rat brain.

Fucosyltransferases (FTs) and various glycosidases that are involved in the biosynthesis or degradation of SSEA-1 (Le(x)) antigens and their precursors in the CNS are developmentally regulated. In forebrain and cerebellum with lactosamine (LacNAc) as acceptor the FT activity was maximal at P15-P22, but with the glycolipid substrate paragloboside (nLc4) the maximal activity in cerebellum was obtained at P10-P15. The FT activity, with these substrates, was insensitive to N-ethylmaleimide (NEM) and the glycolipid product had an alpha1,3 linkage (Fuc to GlcNAc) suggesting similarities of the investigated enzyme to the cloned human and rat FT IV. However, the observation of different patterns of FT activity in isoelectrofocused fractions (pH 3.5-10) with different types of acceptors, and the differential expression of Le(x) containing glycolipids and glycoproteins during development strongly suggest the presence of more than one type of FT during development. Data on developmental expression of the hydrolytic enzymes, alpha-L-fucosidase, beta-D-galactosidase and alpha-D-galactosidase, which can potentially hydrolyse SSEA-1 or its precursors, support the notion that SSEA-1 expression is the result of a dynamic balance between the activity of transferases and hydrolases.

Animals↗
PubMed1981

Beta-galactosidase-neuraminidase deficiency: restoration of beta-galactosidase activity by protease inhibitors.

Beta-Galactosidase was partially restored by protease inhibitors, leupeptin, chymostatin and E-64 in cultured fibroblasts from three patients with beta-galactosidase-neuraminidase deficiency. Pepstatin did not activate this enzyme. Neuraminidase was not affected by any of these compounds in the culture medium. It was concluded that the activating effect was produced by a specific inhibition of thiol proteases.

Cells, Cultured↗
PubMed1997

A novel Arthrobacter beta-galactosidase with homology to eucaryotic beta-galactosidases.

An Arthrobacter beta-galactosidase has homology with the lysosomal acid beta-galactosidases from humans and mice and with a Xanthomonas manihotis enzyme. Phylogenetic analysis of the deduced amino acid sequence showed an unusual pattern, with this procaryotic enzyme clustering within the animal clade. The gene encodes a subunit of 52 kDa, and the enzyme appears to be active as a dimer. The enzyme hydrolyzed substrates with either a beta-1,4 or a beta-1,3 linkage.

Amino Acid Sequence↗
PubMed1976

Krabbe's globoid cell leucodystrophy. Studies on galactosylceramide beta-galactosidase and non-specific beta-galactosidase of leucocytes, cultured skin fibroblasts, and amniotic fluid cells.

Galactosylceramide beta-galactosidase (cerebrosidase) and nonspecific beta-galactosidase activities were measured in both cultured skin fibroblasts and leucocytes from a family with Krabbe's globoid cell leucodystrophy (GLD). The activities of these enzymes were also determined in cultured skin fibroblasts of a patient with GM1 gangliosidosis and in cultured amniotic fluid cells. While cerebrosidase activity was deficient in GLD fibroblasts and leucocytes, its activity in GM1 gangliosidosis fibroblasts was increased. Two forms of each enzyme were found on isoelectric focusing, but in the GM1 gangliosidosis fibroblasts, cerebrosidase activity occurred as a single but intermediate peak. The use of cultured cells in assessing isoenzyme abnormalities associated with certain neurolipidoses is discussed.

Amniotic Fluid↗
PubMed1988

Vaccinia virus recombinants expressing an 11-kilodalton beta-galactosidase fusion protein incorporate active beta-galactosidase in virus particles.

Recombinant plasmids in which vaccinia virus transcriptional regulatory sequences were fused to the Escherichia coli lacZ gene were constructed for insertion of the lacZ gene into the vaccinia virus genome. beta-Galactosidase (beta-gal) was found in some purified recombinant vaccinia virions. By enzyme activity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and microscopic techniques, the evidence suggested that beta-gal accounted for 5% of the total protein in the virion. These recombinant viruses were constructed so that a portion of the coding sequences of a late vaccinia virus structural polypeptide was fused to the amino terminus of beta-gal to produce the fusion protein. Removal of the coding sequences resulted in the complete loss of beta-gal activity. This demonstrated that a vaccinia virus DNA segment from a late structural gene is responsible for the incorporation of beta-gal into the virion.

Base Sequence↗
PubMed1997

In situ histochemical detection of beta-galactosidase activity in lung: assessment of X-Gal reagent in distinguishing lacZ gene expression and endogenous beta-galactosidase activity.

Bacterial lacZ is one of the most commonly used reporter genes for assessing gene transfer to lung. However, lung contains endogenous beta-galactosidase (beta-Gal), which can confound estimation of exogenous lacZ expression by histochemical techniques (i.e., X-Gal) for in situ demonstration of enzyme activity. We investigated several parameters of the X-Gal reaction, including time and temperature of X-Gal exposure as well as lung tissue processing and fixation techniques, and found that none of these could be used to distinguish between endogenous and exogenous beta-Gal activities. The mammalian and bacterial beta-Gal enzymes, however, have pH optima in the acidic and neutral ranges, respectively. Exposing whole lung, lung minces, or mounted frozen sections of lung to X-Gal at mildly alkaline pH (pH 8.0-8.5), minimized detection of endogenous activity in lungs from a variety of species while preserving that resulting from bacterial enzyme activity in a transgenic mouse expressing lacZ. This technique was also useful in distinguishing endogenous activity from that resulting from adenovirus-mediated lacZ gene transfer to diploid lung fibroblasts in primary culture. An appropriate buffer that maintains the desired pH throughout the duration of X-Gal exposure must be used.

Animals↗
PubMed1991

Fabry disease in a large Nova Scotia kindred: carrier detection using leucocyte alpha-galactosidase activity and an NcoI polymorphism detected by an alpha-galactosidase cDNA clone.

Fabry disease is an X linked recessive disorder of glycosphingolipid metabolism resulting from a deficiency of the lysosomal hydrolase alpha-galactosidase (alpha-gal). Measurement of the enzyme activity, however, is not an accurate method for identification of female carriers among at risk relatives of affected males. The alpha-gal cDNA and gene have been cloned previously and found to provide useful probes for the molecular analysis of affected families but these clones have not been available to us. Thus, to analyse Fabry disease in Nova Scotia, especially within a large kindred known to contain 30 affected males and 50 possible carrier females, we isolated an independent cDNA for alpha-gal. Using this clone as a probe, the mutation in the Nova Scotia kindred was shown not to be a major DNA alteration, but was found to be linked to the rarer allele (frequency 0.20) of the polymorphic NcoI site located 3' to the gene. Affected males from two Nova Scotia families who cannot be associated with the kindred by history were also found to have the rarer NcoI allele, which suggests they are, in fact, part of the kindred. The coupling of the mutation to an infrequent marker also helped carrier identification in the kindred where all of 17 obligate carriers examined, including six who were not identified as carriers by enzyme assays, were found to be heterozygous for the RFLP. Thus, DNA analysis can be used for presymptomatic and prenatal diagnosis in most portions of the Nova Scotia kindred affected with Fabry disease.

Base Sequence↗
PubMed1996

Coexistence of two kinds of 6-phospho-beta-galactosidase in the cytosol of Lactobacillus gasseri JCM1031--purification and characterization of 6-phospho-beta-galactosidase II.

Lactobacillus (L.) gasseri JCM1031 has 2 kinds of 6-phospho-beta-galactosidase (P-beta-gal) in the cytosol. P-beta-gal I was already isolated and characterized for our previous paper [Biosci. Biotech. Biochem., 60, 139-141 (1996)]. Another, P-beta-gal II, was purified to homogeneity through several liquid chromatographic steps for this paper. The molecular mass of the purified enzyme was estimated to be 58 kDa by SDS-PAGE. The Km and V(max) for ONPGal-6P were 0.76 mM and 86.0 mumol/min/mg, respectively. Reducing reagents and Fe2+ ion activated the enzyme, but PCMB, Zn2+, and Hg2+ ions, and alkylation reagents strongly inhibited it. Twenty-five residues of the N-terminal amino acid sequence of the enzyme were identified. P-beta-gal II was different from P-beta-gal I in several characteristics.

Amino Acid Sequence↗
PubMed1976

Characterization of T and B antigen-binding cells for beta-galactosidase. I. beta-galactosidase-binding cells in the thymus and spleen of normal mice.

The results reported in this paper demonstrate that the enumeration of cells binding beta-galactosidase (Z) as an antigen, revealed by subsequent substrate hydrolysis, is an excellent method for the detection and study of antigen-binding cells (ZBC). The binding found is specific and is restricted to a small number of lymphocytes that bind a large number of Z molecules via surface receptors. Such ZBC were found at mean frequencies of 150 per 10(6) in the thymus and 200 to 300 per 10(6) in the spleen. The binding cells of both organs were heterogenous with individual ZBC binding from 10(5) to 10(6) molecules of enzyme as determined by substrate hydrolysis, although this might well be an overestimate of the number of actual receptors. The profiles for the frequency of ZBC binding different numbers of molecules were nearly identical for thymus and spleen, in contrast to descriptions of the binding of many other antigens. Receptors responsible for Z binding appear to be superficially located on the cell since they are trypsin-sensitive to a large extent and are not increased by fixation.

Animals↗
PubMed1997

[alpha-Galactosidase gene mutation and its expression product in Fabry disease (alpha-galactosidase deficiency)].

Fabry disease is characterized by a deficiency of lysosomal alpha-galactosidase (alpha-Gal) and the accumulation of glycosphingolipid (e.g. predominantly globotriaosylceramide) in various tissues, mainly in lysosomes of the vascular endothelium. This disorder is currently classified into two clinical phenotypes; classical severe type and atypical variant type. Classical form patients, with clinical manifestations of generalized angiopathy of early onset, usually show no detectable alpha-Gal activity. Recently, there are also atypical form patients with residual alpha-Gal activity and late-onset cardiomyopathy without other systemic manifestations. So far, we identified a number of alpha-Gal gene mutations including partial gene deletions, splicing mutations, nonsense mutations and missense mutations. They were heterogeneous and more than half of them were missense mutations. To clarify the molecular mechanism causing the enzyme defect in the patient, various missense mutations were expressed in COS-1 cells. At least, two groups have been identified; one expressing a mutant enzyme without catalytic activity (non-functional type), and the other expressing catalytically active but unstable mutant enzyme (fragile type). The fragile type mutants were widely present in the different clinical phenotypes from classical severe type to atypical milder type including subclinical Fabry hemizygote, and the mutant enzymes were posttranslationally inactivated and degraded in the cells. The inactivation and degradation were prevented by the addition of substrate analogue; galactose or melibiose. These findings provided us with significant informations on the molecular pathology of the enzyme defect in Fabry disease, and suggested the possibility of a new therapeutic approach for this disease.

Fabry Disease↗