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PubMed1986

A detailed examination of the iodination of beta-galactosidase: stoichiometric inactivation by nonspecific iodination.

The incorporation of 125I, using lactoperoxidase, and the subsequent inactivation of beta-galactosidase in the period when incorporation and inactivation were stoichiometric were investigated in detail. The high pressure liquid chromatographic (HPLC) radioactive profiles of the tryptic peptides of samples taken in the stoichiometric period showed that, although two labelled peptides predominated, there were other labelled peptides. The predominating peptides were shown to be the mono- and di-iodinated forms of the peptide containing Tyr-253. This confirmed the result of an earlier study, but quantitation showed that this iodination accounted for only 15-18% of the total. To show that the other labelled peptides in the HPLC profiles were not merely oxidized or partially digested forms of the peptide containing Tyr-253, two experiments were carried out. In one of the experiments, two of the other labelled peptides were isolated and identified as iodinated forms of the peptide containing Tyr-285 (5-7% of the incorporation). In the other experiment, four additional labelled fractions from the HPLC eluate were treated further with trypsin. No further digestion was observed and thus these peptides did not result from incomplete digestion of the sequence containing Tyr-253. Overall, these results show that, although the incorporation of 125I was stoichiometric with inactivation, no single Tyr was responsible for the inactivation as was tentatively suggested previously. The competitive inhibitor isopropyl-beta-D-thiogalactopyranoside (IPTG) was effective in reducing the rates of inactivation of the enzyme and incorporation of 125I, but the same peptides were labelled in the presence of IPTG as in its absence.

Chromatography, High Pressure Liquid↗
PubMed1981

The bovine genes for phosphoglycerate kinase, glucose-6-phosphate dehydrogenase, alpha-galactosidase, and hypoxanthine phosphoribosyltransferase are linked to the X chromosome in cattle-mouse cell hybrids.

Bovine embryonic trachea cells were hybridized with mouse A9 cells deficient in hypoxanthine phosphoribosyltransferase, and cattle-mouse hybrid cells clones were isolated after HAT/ouabain selection. In these interspecific cell hybrids, bovine glucose-6-phosphate dehydrogenase, alpha-galactosidase, and phosphoglycerate kinase were expressed concordantly with bovine HPRT. Their expression depended on the presence of bovine X chromosome. These data indicated that the genes for G6PD, PGK, and HPRT are linked and can be assigned to the bovine X chromosome.

Animals↗
PubMed1978

beta-Galactosidases in mouse duodenal mucosa.

beta-Galactosidase activity, in fetal mice, first appears at 16 days of gestation and has a pH optimum of 4. In postnatal development the enzyme activity of cell homogenates tends to show bimodal pH at 4 and 5.6. There are two molecular forms of the enzyme, separable both by molecular-sieve chromatography and electrophoresis. One of the molecular forms of the enzyme is active over a wider range of pH (3.2-6.2) and has half as much activity at 5.6 as it does at 4. This isoenzyme is continuously present in both fetal and postnatal stages. The second isoenzyme first appears at birth, is active over a narrower range of pH (4.6-6.2) and inactive at PH 4. The bimodal pH optima observed in postnatal stages in the cell homogenates, appears to be due to the combined activity of the two molecular forms. In isolated brush border membranes, isoenzyme 2 is the only one present. The other organelles (mitochondria, microsomes, lysosomes, nuclei and cytoplasm) have variable proportions of both isoenzymes, as indicated by the activity ratio at pH 4/5.6.

Aging↗
PubMed1980

Preparation of water-soluble high-molecular weight substrates for beta-D-galactosidase.

Two types of high-molecular water-soluble substrates of beta-D-galactosidase were prepared. Substrate I contains beta-D-[3H]-galactopyranosyl moieties linked, through a hydrocarbon bridge, to a polymeric dialdehyde (oxidized starch) backbone (molecular weight 6,000); in substrate II the backbone is poly-L-lysine (molecular weight 80,000). In the presence of Triton X-100, but not in its absence, D-[3H]-galactose is split from the substrates by homogenates of normal mouse liver or pancreas. It is suggested that substrates I and II could be used to test the integrity of lysosomal and other cellular membranes, and to assess the extent of cellular injury.

Aldehydes↗
PubMed1983

Heterogeneity of beta-galactosidase from rabbit spleen. Separation and characterization of different forms.

Two forms, I and II, of an acid beta-galactosidase from rabbit spleen were separated by DEAE-cellulose chromatography and then characterized. Both forms of the enzyme showed different heat-stability (form I being heat-labile and form II heat-stable), and different pI (6.7 for form I and 5.3 and 6.7 for form II). Their gel filtration patterns were also different: form I was resolved in a single peak of mol. wt. 75,000, whereas form II was resolved in one or two peaks of mol. wt. 120,000 and greater than 200,000, depending on the pH of elution. However, both forms had similar pH stability and behavior toward alpha-methyl-beta-D-galactopyranoside, alpha-methyl-beta-D-glucopyranoside, urea and KCl. Differences in pH optima, optimal temperature and Km values were not marked.

Animals↗
PubMed2005

GH97 is a new family of glycoside hydrolases, which is related to the alpha-galactosidase superfamily.

BACKGROUND: As a rule, about 1% of genes in a given genome encode glycoside hydrolases and their homologues. On the basis of sequence similarity they have been grouped into more than ninety GH families during the last 15 years. The GH97 family has been established very recently and initially included only 18 bacterial proteins. However, the evolutionary relationship of the genes encoding proteins of this family remains unclear, as well as their distribution among main groups of the living organisms. RESULTS: The extensive search of the current databases allowed us to double the number of GH97 family proteins. Five subfamilies were distinguished on the basis of pairwise sequence comparison and phylogenetic analysis. Iterative sequence analysis revealed the relationship of the GH97 family with the GH27, GH31, and GH36 families of glycosidases, which belong to the alpha-galactosidase superfamily, as well as a more distant relationship with some other glycosidase families (GH13 and GH20). CONCLUSION: The results of this study show an unexpected sequence similarity of GH97 family proteins with glycoside hydrolases from several other families, that have (beta/alpha)8-barrel fold of the catalytic domain and a retaining mechanism of the glycoside bond hydrolysis. These data suggest a common evolutionary origin of glycosidases representing different families and clans.

Amino Acid Sequence↗
PubMed1984

Developmental changes in enzyme activities in fetal and neonatal rabbit lung. Cytidylyltransferase, cholinephosphotransferase, phospholipases A1 and A2, beta-galactosidase, and beta-glucuronidase.

Lungs were obtained from rabbit fetuses (on each day from d 24 to d 30 of gestation), neonates and adults, and were fractionated for enzyme assays. The developmental profile of cytidylyltransferase shows a decrease in specific activity from d 25 to d 29 (P less than 0.05) then a sharp rise from d 30 to adult values in d 0 neonates (P less than 0.05). Cholinephosphotransferase specific activity changes little from d 25 to birth, apart from a non-significant peak on d 29. There is a sharp rise from neonatal d 0 to adult values on d 1 (P less than 0.01). The specific activity of microsomal phospholipase A2 declines from d 25 to reach adult values in the neonate (P = 0.05). In contrast, the specific activity of lysosomal phospholipase A2 rises from d 24-28 then falls in the neonate (P less than 0.05). Adult values are higher than those in the fetus and neonate. Three other lysosomal enzyme specific activities rise to d 28 then decline: phospholipase A1, beta-galactosidase, and beta-glucuronidase. The results demonstrate that the level of microsomal phospholipase A2 does not control the extent of remodelling of phosphatidylcholine for surfactant production. Lysosomal phospholipase A2 only increases in parallel with the other lysosomal enzymes, indicating an increase in the number of lysosomes in the lung.

Age Factors↗
PubMed1978

Enzyme immunoassay of human chorionic gonadotropin employing beta-galactosidase as label.

An enzyme-linked immunoassay was applied to the determination of hCG, a glycoprotein hormone usually assayed by RIA. For this purpose, an enzyme hormone conjugate was prepared by reacting hCG with beta-D-galactosidase (beta-Gal.) of E. coli in the presence of N-(m-maleimidobenzoyloxy) succinimide (MBS) as coupling reagent. The conjugate, after purification by affinity and gel chromatographies, was shown to exhibit sufficient enzyme activity and immunoactivity. The immunoassay of hCG was performed by the double antibody method and, using this assay, 0.4-250 mIU/ml hCG were detectable. This was about 10 times as sensitive as the RIA. Difficulty was experienced when this method was utilized for the determination of hCG in plasma samples from patients. Since the presence of the plasma may have affected this assay method, the following improvements were made: 1) the same volume of hormone-free plasma was added to the standard solutions of hCG, and 2) the volume of plasma sample was 10 microliter. The performance and validity of this assay were comparable to the RIA using [125I]hCG as tracer. The dose-response curves of both assay have the same slope and there was no significant difference between the values (correlation coefficient, Y = 0.96X + 1.53).

Acylation↗
PubMed1986

A family with beta-galactosidase deficiency: three adults with atypical clinical patterns.

Three adult patients in a single family showed severe myoclonus, ataxia, and pyramidal signs. Enzymatic analysis of lymphocytes, plasma, and cultured skin fibroblasts showed marked deficiency of beta-galactosidase activity, more profound with GM1 ganglioside than with another natural substrate, asialofetuin. Other lysosomal hydrolases were normal. Although the physical signs were similar to those of types 1 and 2 GM1 gangliosidosis, none had bony abnormalities.

Adult↗
PubMed1981

Enzyme immunoassay of neocarzinostatin using beta-galactosidase as label.

A novel convenient procedure was introduced for enzyme labelling of neocarzinostatin (NCS) with beta-D-galactosidase using a new hetero-bifunctional reagent N-(gamma-maleimidobutyryloxy) succinimide (GMBS). With the enzyme labelled NCS and a rabbit anti-NCS serum which was elicited in a rabbit immunized with NCS in complete Freund's adjuvant, a highly sensitive enzyme immunoassay which can quantify a femto mol order NCS was developed. Accuracy and precision of the assay as well as a comparison with the immunodiffussion method were studied with satisfactory results. This enzyme immunoassay of NCS was applicable to monitoring serum NCS levels of patients in clinical treatment of the antitumor agent.

Antibiotics, Antineoplastic↗
PubMed1990

Studies on the enzyme immunoassay of bio-active constituents contained in oriental medicinal drugs. V. Preparation of bovine serum albumin conjugate and beta-galactosidase labelled antigen for enzyme immunoassay of 3 beta-(monoglucuron-1' beta-yl)-18 beta-glycyrrhetic acid.

In order to prepare an immunogen for enzyme immunoassay of 3 beta-(monoglucuron-1'-beta-yl)-18 beta-glycyrrhetic acid (3MGA), which was isolated from a patient with glycyrrhizin-induced pseudoaldosteronisms, benzyl glycyrrhetate (3) was allowed to react with an acetobromosugar (2) in the presence of silver carbonate to give benzyl 3 beta-(methyl 2',3',4'-triacetyl-glucuron-1' beta-yl)-glycyrrhetate (5) and methyl 3',4'-diacetyl-alpha-1',2'-O-[1-(benzyl glycyrrhet-3 beta-yl)- ethylidene]-D-glucuronate (4). On the other hand, this reaction was carried out in the presence of mercuric cyanide in nitromethane to give compound 5, benzyl 3 beta-acetyl glycyrrhetate (6) and benzyl 11-oxo-A-neooleana-3(5),12-dien-3-oate (7). 4-Aminomethylcyclohexanecarboxylic acid and glycine were introduced as chemical bridges at C-30 of 3 beta-(tert-butylglucuron-1' beta-yl)-glycyrrhetic acid (11) derived from compound 5. The former bridge was used to prepare an immunogenic conjugate with bovine serum albumin, and the latter bridge was used for antigen labelled with beta-galactosidase.

Animals↗
PubMed1986

Effect of various conditions on the formation of oligosaccharides in milk treated with beta-galactosidase.

Fresh pasteurized milk was inoculated with beta-galactosidase from two different microbial sources at three levels and analyzed for oligosaccharides by high performance liquid chromatography. Five oligosaccharides were observed in the course of hydrolysis. However, only two of these showed measurable increases in concentration. Rate of oligosaccharide formation during hydrolysis was influenced by source and amount of enzymes, reaction time, and temperature. Maximum concentrations of the two oligosaccharides occurred between .5 and 3 d at 7 degrees C and between 1 and 3 d at 1 degrees C, depending on the level of the enzyme used. The higher level of enzyme formed a higher concentration of oligosaccharides than the low level, except at 37 degrees C. After maximum concentration was reached, the two oligosaccharides decreased following hydrolysis, but rate of decrease was dependent upon time, temperature, and enzyme concentration. Hydrolysis of the oligosaccharide was faster at 7 degrees C and at the higher enzyme concentration. Maximum concentration of oligosaccharides was .374 g/100 g milk but was negligible after 7 d, except when the low level of enzyme was used. The total concentration of the oligosaccharides formed in enzyme-treated milk was insignificant.

Animals↗
PubMed1987

Purification and characterization of a beta-galactosidase from Fusarium oxysporum var. lini.

Beta-D-Galactosidase was purified from a cellular extract of Fusarium oxysporum var. lini by heat shock and successive chromatography on DEAE-cellulose DE-52 and Sephadex G-100. The purified enzyme was homogeneous on SDS gel electrophoresis. It was inhibited by divalent cations such as Zn++, Mg++, and Ca++. The Michaelis constant and maximum velocity values for o-nitrophenyl beta-D-galacto-pyranoside were 6.76 mM and 816.7 mumol X mg protein-1 X min-1. The isoelectric point was 3.83, and the optimal pH and temperature were 5.0 and 55 degrees C. The estimated molecular weight of the enzyme was 224,000 by gel filtration and 36,300 by SDS-PAGE. The enzyme was considered a hexamer. o-Nitrophenyl-beta-D-galacto-pyranoside hydrolysis was activated by lactose, suggesting an allosteric nature of the enzyme.

Chromatography, Gel↗
PubMed1979

beta-Galactosidase-inhibiting new isoflavonoids produced by actinomycetes.

Six isoflavonoids having beta-galactosidase inhibiting activity were isolated from the culture filtrate of Streptomyces xanthophaeus. Their structures were determined by spectral analyses to be daidzein, daidzein 7-alpha-L-rhamnoside, daidzein 4',7-di-alpha-L-rhamnoside, genistein, genistein 7-alpha-L-rhamnoside and genistein 4',7-di-alpha-L-rhamnoside.

Actinomycetales↗
PubMedDate not supplied

[Lysosomal beta-galactosidase properties and the molecular genetics of GM1 gangliosidosis].

Review of the data is presented on the hereditary disease gangliosidosis GM1 and on the enzyme beta-galactosidose, deficiency of which is responsible for this disease. Heterogeneity of the disease and existence of various forms of beta-galactosidase are considered. Possible correlation is discussed between the defects of the enzyme forms detected and the type of the disease.

Adult↗
PubMed1979

Distribution of beta-galactosidase in the cerebral hemisphere of Calotes versicolor.

The histoenzymological mapping of beta-galactosidase in various nuclei and fiber tracts of reptilian cerebral hemisphere (Calotes versicolor) has been reported for the first time. Almost all the enzymatic preparations demonstrate mild activity in the nuclei except one nucleus (HPD) which reveals intense activity. On the other hand, the fiber tracts, in view of the intense activity of the enzyme, have presented themselves as well delineated tracts along their entire courses so much so that in certain nuclei they can be clearly distinguished passing through the nuclei. The metabolic significance of the enzyme in various locales has been discussed.

Animals↗