Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Drosophila melanogaster cell lines Kc and Ca and clones FC and RF6, cultured in vitro, have no detectable beta-galactosidase (beta-galactoside galactohydrolase, EC 3.2.1.23) activity (as measured by hydrolysis of o-nitrophenyl-beta-D-galoctoside). Ecdysterone, a hormonal steroid of critical importance in insect physiology, clearly induces beta-galactosidase activity in D. melanogaster cells cultured in vitro. Induction occurs in cell lines or clones known to be sensitive to ecdysterone (K, Ca, and Fc) and does not occur in clones known to be resistant to the hormone (RF6). Some properties of the hormone-induced beta-galactosidase activity were studied. The Km for o-nitrophenyl galactoside is 0.35 mM and the Ki for lactose is 12 mM (similar to those of Escherichia coli beta-galactosidase); the activity can be recovered after sodium dodecyl sulfate treatment; the enzyme is a tetramer (Mr of the monomer is 64,000).
 ...
PMID:beta-Galactosidase is induced by hormone in Drosophila melanogaster cell cultures. 10 99

1. Human liver acid beta-galactosidase A2 and A3 were isolated by chromatography on concanavalin A-Sepharose 4B, Sepharose 6B, and Sepharose 4B-6-aminohexyl 1-thio-beta-D-galactopyranoside. beta-Galactosidase A2 and A3 were purified to final specific activities of 45.5 and 20.6 mumol/min per mg respectively with 4-methylumbelliferyl beta-D-galactopyranoside as substrate. 2. Form A2 had a mol.wt. of 150000 +/- 15000 (gel filtration) and appeared as a single band of protein (mol.wt 65000 +/- 1000) on electrophoresis in the presence of sodium dodecyl sulphate. 3. Form A3 had a mol.wt. (gel filtration) of 660000 +/- 66000. On electrophoresis in the presence of sodium dodecyl sulphate, form A3 appeared as a major band of protein (72% of total) of mol.wt. 65000 +/- 1000 and minor protein bands of mol.wt. 44000 +/- 1000 and 26,000 +/- 1000 and 22000 +/- 1000. 4. Gel-filtration chromatography of purified beta-galactosidase A3 generated approximately equal amounts of forms A3 and A2. beta-Galactosidase A1 was not detected by gel-filtration chromatography of partially or highly purified preparations of forms A2 and A3. 5. Both forms A2 and A3 had identical isoelectric points of 4.42 +/- 0.02. The data suggest that forms A2 and A3 are dimeric and multimeric forms of beta-galactosidase A1. 6. Amino acid analysis of beta-galactosidase A2 gave a ratio of acidic to basic amino acids of 2.6:1. 7. beta-Galactosidase A2 contained 7.5% carbohydrate by weight and sialic acid, D-galactose, D-glucosamine and D-mannose were present in the molar proportions 1.1:1.0:1.7:2.7.
 ...
PMID:Characterization of purified human liver acid beta-D-galactosidases A2 and A3. 10 12

Endo-beta-galactosidase, a glycosidase that hydrolyzes Gal beta 1-4 GlcNAc linkages in glycoconjugates, has been used to probe the plasma membrane of human erythrocytes. Coomassie blue staining of stroma components separated by sodium dodecyl sulfate-acrylamide gel electrophoresis indicates that treatment of red cells with endo-beta-galactosidase converts Protein 3, the anion transporter of the erythrocyte, to a more compact staining band. No other components detected by Coomassie staining are affected. Following labeling of red cells with galactose oxidase + NaB3H4, 45 to 50% of the [3H]galactose residues can be released by endo-beta-galactosidase. In contrast, only 5% of the label incorporated by treatment with periodate + NaB3H4, can be removed. [3H]Galactose residues are released from three components: Protein 3, Band 4.5, and the megaloglycolipids. The susceptibility of these components to endo-beta-galactosidase, together with the high content of Gal and GlcNAc present in Protein 3 and the megaloglycolipids, suggests that the erythrocyte membrane contains several components with N-acetyllactosamine repeating units, a structure commonly found in connective tissue glycoconjugates.
 ...
PMID:Effect of endo-beta-galactosidase on intact human erythrocytes. 11 98

Thyroxine-binding globulin (TBG), prepared from human serum by an improved purification method, was treated with a mixture of neuraminidase, beta-galactosidase, alpha-mannosidase, and beta-N-aectylglucosaminidase, which resulted in the removal of approximately 86% of saccharides. Purification by thyroxine-Sepharose affinity chromatography gave a homogeneous protein as shown by equilibrium sedimentation and sodium dodecylsulfate-polyacrylamide gel electrophoresis. Amino acid and NH2-terminal sequence analysis indicated that the protein moiety was intact. Deglycosylation had no effect on the stoichiometry of the binding of L-thyroxine as shown by tryptophanyl fluorescence quenching and equilibrium dialysis at pH 8.6 and 25 degrees C. However, the affinity constant for L-thyroxine was reduced from 1.6 X 10(9) M-1 to 0.58 X 10(9) M-1. Analysis of radioimmunoassay data revealed that deglycosylation resulted in a slight decrease of the affinity constant for anti-TBG antibody from 3.9 X 10(10) M-1 to 1.8 X 10(10) M-1. These results suggest that the polypeptide moiety, rather than the heterosaccharides, contains the antigenic determinants. Removal of the majority of the heterosaccharides of TBG has only a minor effect on its immunoreactivity and on the binding of thyroid hormone.
 ...
PMID:Effect of deglycosylation on the binding and immunoreactivity of human thyroxine-binding globulin. 11 1

We have purified beta-galactosidase and beta-glucuronidase from macrophages of thioglycollate-treated mice using concanavalin A chromatography and immunoprecipitation. The apparent molecular weight of the beta-galactosidase subunit, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, changed during a long term pulse-chase experiment. Following a 1-h pulse with [3H]leucine, radiolabel was present exclusively in an Mr = 82,000 form. However, after a 3-h chase in medium containing unlabeled leucine, most label migrated at Mr = 63,000, and at 24 h, all label was in the Mr = 63,000 form. Electrophoresis of peptides produced by cyanogen bromide cleavage of immunoprecipitates demonstrated structural similarities between precursor and mature forms. A mutation in the mouse, which is known to depress the rate of synthesis of beta-galactosidase in many cell types, proportionately decreased incorporation of [3H]leucine into both the Mr = 82,000 and 63,000 forms. Therefore, by kinetic, structural, and genetic evidence, the large molecular weight beta-galactosidase is a precursor of mature macrophage enzyme. No precursor of the Mr = 75,000 subunit of beta-glucuronidase was detected.
 ...
PMID:Biosynthesis of two lysosomal enzymes in macrophages. Evidence for a precursor of beta-galactosidase. 11 27

It has been known for a long time that hearing deficits may coexist in patients with thyroid disease, but without definite morphologic evidence present to correlate gland dysfunction with hearing disturbances. To clarify this relationship between thyroid dysfunction and hearing disturbances, the guinea pig was employed as an experimental model. 70 animals were thyroidectomized, and maintained in a hypothyroid state for varying periods of time. The animals were then sacrificed, and various histochemical studies then performed. These studies included analysis for glycosidase (beta-galactosidase, beta-glucuronidase, n-acetyl-beta-glucosamide), non-specific esterases, sulfatases, sulghydryl groups as well as mucous substances within the cochlea and saccus endolymphaticus of the experimental animals. Results indicated that hyaluronidase-sensitive mucous substances were increased in the scala of the inner ear. As a consequence of increased deposition of acid mucopolysaccharides, the relationship of potassium to sodium in endolymph and perilymph was found markedly altered. Marked swelling of the chambers of the inner ear was noted, and believed to represent hydropic induction by acid mucopolysaccharide-with consequent alteration of electrolyte relationships ("Electrochemical Theory").
 ...
PMID:[Animal experiment histological-histochemical studies on the development of hearing disorders related to hypothyroidism]. 12 84

Studies have been conducted to characterize further the interaction between 125I-labeled bovine thyrotropin (TSH) and bovine thyroid plasma membranes. Sequential subcellular fractionation of thyroid homogenates yielded preparations of progressively greater specific binding activity, highest activity being found in fractions previously shown to contain predominately plasma membranes (Amir, S. M., Carraway, T.F., Kohn, L.D., and Winand, R.J. (1973) J. Biol. Chem. 248, 4092-4100). Although binding of 125I-TSH by plasma membranes was greatest at pH 6.0, studies were conducted at pH 7.45 as well as pH 6.0, and results obtained differed quantitatively, but not qualitatively. Binding was maximal at 0 degrees, 15 degrees, and 22 degrees and steady state values remained unchanged for at least 22 hours. At 37 degrees, binding was decreased by 40% at 1 hour; the loss was even greater (65%) at 50 degrees. A similar loss of binding was evident when membranes were preincubated without TSH at 37 degrees or higher and were then incubated with 125I-TSH at 0 degrees. Lineweaver-Burk analysis indicated that preincubation resulted in loss of receptor sites without change in affinity of residual receptors. Addition of Ca2+ (1 to 10 mM) to the preincubation medium prevented the effect of preincubation at 37 degrees by preserving the number of receptor sites without altering their affinity. Under similar conditions, Na+ and K+ were without protective effect. Membranes bound 45Ca2+ in a specific and saturable manner. Scatchard plots indicated a dissociatiion constant (Kd) of 9 X 10(-5) M and a capacity (n) of 54 nmol/mg of membrane protein. 45Ca2+ was also displaced from membranes by Mg2+ and Mn2+. Ca2+ had a biphasic effect on binding; low concentrations (1 to 10 muM) added to the incubation mixture stimulated binding, while higher concentrations (0.1 mM) caused inhibition. Mg2+ and Mn2+, at comparable concentrations, were also inhibitory, Na+ and K+ less so. In the case of Ca2+, both the stimulatory and inhibitory concentrations were lower than those required to achieve saturation of Ca2+-binding sites. Proteolytic enzymes (trypsin, alpha-chymotrypsin, and pronase) sharply reduced binding of 125I-TSH, owing to a decrease in receptor sites. Phospholipases A and C enhanced binding of TSH, while neuraminidase and beta-galactosidase were without measurable effect.
 ...
PMID:Properties of the interaction between bovine thyrotropin and bovine thyroid plasma membranes. 18 81

The induction of nephrotoxic nephritis in rats with rabbit antibodies preparation results in proteinuria, hypoproteinemia and hyperlipidemia with little glomerular lesions. A study of some hydrolases in cortex and medulla on one hand and glomerular and tubules on the other, showed changes in the activities of following enzymes. 1) A 20-30 % decrease in Na+, K+ dependent ATP-ase in whole kidney. 2) A 20 % decrease in beta-galactosidase activity in glomerular and medulla. 3) A 20 % increase of arylsulphatase A activity in tubules. These results are discussed in the light of the present knowledge of sulphatide metabolism in kidney.
 ...
PMID:[Experimental nephrotic syndrome in the rat. Biologic parameters and study of several hydrolases in different purified kidney fractions]. 20 50

A protein, present in bovine seminal plasma, initiates forward motility in immature, immotile caput spermatozoa that have been incubated with a cyclic AMP phosphodiesterase inhibitor. An improved motility assay was developed to study this process and the protein involved. This forward motility protein exhibits multiple forms when fractionated on the basis of charge or molecular weight. Molecular sieving in urea or sodium dodecyl sulfate and dithiothreitol results in a single peak of activity which will re-form the larger aggregates in the absence of these agents. The molecular weight of this monomeric motility protein, as estimated from molecular sieving under these dissociating conditions, is 37,500. The forward motility protein can be partially purified by heat treatment, gell chromatography in urea, and affinity chromatography on concanavalin A/agarose. Enzymatic treatments further suggest a glycoprotein nature, i.e. treatment with beta-galactosidase, neuraminidase, alpha-mannosidase, or galactose oxidase reduces its activity by 50%; treatment with trypsin completely abolishes forward motility protein activity. On the basis of concurrent studies on the activity, properties, and distribution of forward motility protein in bovine body fluids, it is suggested that this protein is involved in the development of the capacity for motility as sperm traverse the epididymis.
 ...
PMID:Bovine sperm forward motility protein. Partial purification and characterization. 21 Nov 30

Ten strains of Propionibacterium shermanii were tested for beta-galactosidase (beta-gal) activity. Of these ten strains, five yielded enhanced enzyme activity when cell suspensions were treated with toluene-acetone; on solvent treatment, the remaining five lost a considerable portion of the activity found in whole-cell suspensions. By using a strain yielding decreased activity upon solvent treatment, explanations for the loss in activity were sought through assays for possible alternative beta-galactoside utilization mechanisms. When this strain was assayed for beta-D-phosphogalactoside galactohydrolase by using orthonitrophenyl-beta-D-galactopyranoside-6-P04 as a substrate, the activity was wither lower or indiffernt as compared with beta-gal activity determined simultaneously. Cell suspensions of P. shermanii 7 and 22 (strains chosen for further work) grown separately on the individual substrates (lactose, glucose, galactose, and sodium lactate) did not show significant differences in beta-gal activity. Optimal temperature for beta-gal activity in untreated and toluene-acetone-treated cell suspensions of strain 7 was 52 C. With strain 22, of the temperatures tested, maximal activity in untreated cell suspensions was noted at 58 C and with solvent-treated cells at 32 C. In the cell-free extract (CFE) system, both strains exhibited maximal activity at 52 C. Optimal pH for untreated and solvent-treated cell suspensions of both strains was around 7.5. In the P. shermanii 22 CFE system, maximal activity occurred at pH 7.0; pH had very little effect on enzyme activity in P. shermanii 7 CFE. Sodium or potassium phosphate buffers in the assay system yielded the best activity. In the CFE system of these two strains, Mn2+ was definitely stimulatory, but in untreated and solvent-treated cell systems of these strains presence or absence of Mn2+ in the assay system had variable effects on enzyme activity. Maximal beta-gal activity was noted in P. shermanii 7 cells harvested after 28 h of growth at 32 C in sodium lactate broth. Sulfhydryl-group blocking agents inhibited enzyme activity in P. shermanii 22 CFE; the inhibition was partly reversed by dithiothreitol.
 ...
PMID:Beta-galactosidase of Propionibacterium shermanii. 23 59


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>