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

The ebg beta-galactosidase of Escherichia coli K-12 strain LC110 has been purified and characterized. Strain LC110 is a Lac+ revertant of a mutant with a deletion of the lacZ beta-galactosidase gene. Its new ebg beta-galactosidase activity was shown to be due to a discrete protein, immunologically unrelated to lacZ beta-galactosidase. Its kinetics of action conformed to those of a simple conventional enzyme. With o-nitrophenyl-beta-D-galactoside as substrate, the Vmax was 11,200 nmol/min per mg of enzyme, the Km was 5 mM, and the activation energy was 12,400 cal/mol. Corresponding values for lacZ beta-galactosidase of wild-type E. coli K-12 were 350,000 nmol/min per mg of enzyme, 1.3 mM, and 8,000 cal/mol. A series of sugars has been examined as competitive inhibitors of ebg beta-galactosidase. Kinetic analyses suggest that ebg beta-galactosidase has a particularly high affinity for galactosamine and gamma-galactonolactone, binds galatose more tightly than lactose, and shows a general preference for monosaccharides rather than beta-galactosides. We conclude that the ebg beta-galactosidase may have arisen by modification of a gene involved with the metabolism of a monosaccharide, possibly a 2-amino sugar.
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PMID:Isolation and characterization of the newly evolved ebg beta-galactosidase of Escherichia coli K-12. 24 45

A 14-year-old white girl with mild dysostosis multiplex, odontoid hypoplasia, short stature, cloudy corneas, keratansulfaturia, but without detectable central nervous system abnormalities was referred with the diagnosis of Morquio syndrome. Clinical and roentgenographic findings were minimal compared to those of typical patients with the Morquio syndrome, MPS IV. Beta-Galactosidase activity in extracts of the patient's cultured fibroblasts was deficient, while that of galactosamine-6-sulfate sulfatase was normal. Conjunctival biopsy revealed intracytoplasmic vacuoles typical of lysosomal storage diseases. It is postulated that in this patient the deficiency of a beta-galactosidase is responsible for inadequate degradation of keratan sulfate and the appearance of a mild form of the Morquio syndrome (MPS IVB).
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PMID:Morquio-like syndrome with beta galactosidase deficiency and normal hexosamine sulfatase activity: mucopolysacchariodosis IVB. 41 14

We report here the study of the glycosylation pattern of human recombinant (r) IL2 expressed in a Chinese hamster ovary (CHO) cell line. The human rIL2 secreted by this high-producing recombinant CHO cell line was metabolically radiolabelled with [35S]-methionine, or with [3H]-glucosamine and [3H]-galactose, purified to homogeneity, and then characterized. The electrophoretic analysis of the [35S]-methionine-labelled proteins present in the culture medium of the CHO cell line showed that the rIL2 represents approximately 12% of the total secreted proteins. Furthermore, pulse-chase experiments showed that the glycosylated rIL2 is synthesized and secreted within 30 min. The point of attachment and the structure of the carbohydrate moiety of the rIL2 was determined by: amino-terminal sequencing and fingerprint analysis of the 3H-labelled rIL2, mass spectroscopy of the amino-terminal tryptic octapeptide, and carbohydrate analysis after enzymatic (Vibrio cholerae neuraminidase and Aspergillus oryzae beta-galactosidase) or sulfuric acid hydrolysis. The results indicate that the recombinant protein possesses a sugar moiety O-linked to the threonine residue at position 3 of the polypeptide chain, and that sialic acid, galactose and N-acetyl galactosamine are components of this carbohydrate moiety. Taken together these results suggest that the recombinant molecule is identical to natural IL2.
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PMID:Closely related glycosylation patterns of recombinant human IL-2 expressed in a CHO cell line and natural IL-2. 210 57

The binding of von Willebrand factor (vWF) to platelet membrane glycoprotein Ib (GpIb) facilitates platelet adhesion to vascular subendothelium. In this study, we provide evidence that the vWF binding site is on glycocalicin (GC), a proteolytic fragment of GpIb, and we examine the role of the carbohydrate portion of GC on that binding. The binding to platelets of 6D1, a monoclonal antibody that recognizes an epitope on GpIb and blocks ristocetin-induced vWF binding to platelets, was inhibited by purified GC. In addition, purified GC inhibited ristocetin-dependent binding of 125I-labeled vWF to platelets. Since GC contains 60% carbohydrate by weight, we assessed the role of carbohydrate sequences on its interaction with antibody 6D1 and vWF. Based on the known sequence of the major oligosaccharide chain of GC--N-acetyl neuraminic acid, galactose, N-acetyl glucosamine, N-acetyl galactosamine--we treated GC sequentially with neuraminidase, beta-galactosidase, and beta-N-acetylglucosaminidase. Removal of sialic acid and galactose residues did not affect GC binding. Removal of N-acetyl glucosamine residues did not affect GC binding to 6D1 but did decrease the ability of GC to inhibit vWF binding to platelets, increasing the concentration needed to inhibit binding by 50% (IC50) 40-fold. This suggests that a portion of the oligosaccharide chains on GC contributes to the vWF binding activity of this molecule.
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PMID:Partial characterization of a binding site for von Willebrand factor on glycocalicin. 300 Apr 77

The mechanism of Eikenella corrodens adherence to human buccal epithelial cells in vitro was studied. Initial experiments to determine the optimal conditions for adherence of E. corrodens to buccal epithelial cells showed that adherence was dependent on time, temperature, bacterial concentration, and pH. Different strains of E. corrodens varied in their ability to adhere, and strain 1073 showed the greatest ability in adherence. Strain 1073 was selected for studies of adherence mechanisms. Trypsin treatment or heating (100 degrees C, 10 min) of the bacterial cells abolished their capacity to adhere to buccal epithelial cells. Treatment of buccal epithelial cells with trypsin also abolished adherence of E. corrodens 1073, whereas neuraminidase treatment of buccal epithelial cells enhanced the adherence. The adherence was inhibited by ethylenediaminetetraacetic acid and restored by adding Ca2+. The adherence was remarkably inhibited by sugars containing D-galactose and n-acetyl-D-galactosamine. Treatment of neuraminidase-treated epithelial cells with sodium metaperiodate or alpha- and beta-galactosidase did not decrease the adherence. These data suggest that adherence of E. corrodens 1073 to human buccal epithelial cells may require the interaction of lectin-like proteins on the bacterial surface with galactose-like receptors on the surface of epithelial cells.
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PMID:Eikenella corrodens adherence to human buccal epithelial cells. 626 Jun 61

Two sisters and one brother, all with normal intelligence and no evidence of neurological abnormality, present progressive spondyloepiphyseal dysplasia, stunted growth, corneal opacities, and increased keratansulfaturia. Cultured skin fibroblasts from one of the children showed a remarkable deficiency of acid beta-galactosidase in association with normal activities of N-acetylgalactosamine-6-sulfate sulfatase and sialidase. Acid beta-galactosidase was also deficient in leukocytes of two children. Leukocytes of the parents exhibited intermediate activities, which suggests the primary nature of beta-galactosidase deficiency. Patients with MPS IV-B may be severely affected.
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PMID:Morquio-B disease, spondyloepiphyseal dysplasia associated with acid beta-galactosidase deficiency. Report of three cases in one family. 640 99

Two male patients, aged 6 and 25, both with normal intelligence and absence of neurological abnormalities, exhibited dysostosis multiplex, dwarfism, odontoid anomalies, cloudy corneas, exessive excretion of keratan sulfate, and abnormal urinary oligosaccharides. Leukocytes and fibroblasts of both patients were deficient in acid beta-galactosidase (beta-gal) and normal in N-acetylgalactosamine-6-sulfate sulfatase, the deficient enzyme in classical Morquio syndrome. The beta-gal deficiency was not due to an endogenous inhibitor, and the parents exhibited intermediate activities. Deficient beta-gal activity was observed toward p-nitrophenyl-beta-galactoside, 4-methylumbelliferyl-beta-galactoside (4 MU-beta-gal), lactose, GM1 ganglioside, keratan sulfate, and asialofetuin (ASF). Under standard assay conditions, the residual activity was similar for all substrates tested. Toward p-nitrophenyl-beta-glactoside, the mutant enzyme behaved as a Km variant.
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PMID:Morquio syndrome (mucopolysaccharidosis IV B) associated with beta-galactosidase deficiency. Report of two cases. 644 39

Three major glycoproteins of calf thyroid plasma membranes were preferentially solubilized by chloroform/methanol extraction and recovered along with glycolipids in the aqueous phase. After removal of lipid from this extract, a fraction was obtained which accounted for about 20% of the carbohydrate of the membrane but only 2% of its peptide weight. Partial resolution of the components could be achieved by filtration on Bio-Gel A-5m, while preparative polyacrylamide gel electrophoresis resulted in the isolation in homogeneous form of approximately equal amounts of the three glycoproteins which were designated as GP-1, GP-2, and GP-3, in order of their increasing mobility. These purified glycoproteins appeared on electrophoresis as single components by periodic acid-Schiff staining as well as by distribution of radioactivity following 3H or 14C labeling. Molecular weights of 100,000, 59,000, and 20,000 were estimated for the three components on the basis of their retardation coefficients. The total carbohydrate content by weight determined for GP-1, GP-2, and GP-3 was 56, 57, and 79%, respectively. The sugar constituents were mannose, galactose, fucose, glucosamine, galactosamine, and sialic acid, which were present in the following mol per cents: GP-1, 13:32:5:24:13:12; GP-2, 20:28:3:32:5:11; GP-3, 12:36:2:34:6:10. Studies performed with various lectins (Bandeiraea simplicifolia I and I (B4), wheat germ, Ricinus communis, and soybean) on the gycoproteins, either native or after treatment with glycosidases (alpha- or beta-galactosidase, neuraminidase), indicated that sialic acid and alpha-linked galactose were in terminal positions, beta-galactosyl residues were internally located, and chains containing the sequence sialic acid-N-acetylgalactosamine were present.
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PMID:Isolation and characterization of three major glycoproteins from thyroid plasma membranes. 677 52

A recently identified, high m.w. human tumor antigen, reactive with monoclonal antibody (MAb) PD41 and designated prostate mucin antigen (PMA), was found to have expression highly restricted to prostate carcinomas. Both biochemical and immunological characteristics of this antigen and its relationship to other tumor-associated mucins and various species of submaxillary mucins were evaluated. Immunohistochemical examination of submaxillary tissues revealed differential expression of this antigen and other human tumor-associated mucins, with MAb PD41 expression found only in bovine submaxillary gland serous cells. Neuraminidase treatment enhanced antibody binding by 50%, suggesting partial masking of the PD41 epitope by sialic acid. Antigenicity was reduced by treatment with alkaline-borohydride, sodium metaperiodate, beta-galactosidase, O-glycanase, and various proteolytic enzymes. MAb PD41 antibody binding also could be significantly reduced by selected lectins and sugars suggesting that the immunodominant carbohydrate involved in the epitope was an O-linked oligosaccharide containing N-acetyl galactosamine as a major component. This antigen was further distinguished from T, Tn, or Sialyl-Tn antigens and blood group carbohydrate antigens by radioimmunometric analyses. Cross-blocking and double determinant RIA experiments also showed a distinction between the PD41 epitope and several well-characterized tumor-associated mucin antigens such as MUCI, CEA, M344, OCI25, and AR3 as well as bovine submaxillary core protein. Our results indicate that the PD41-reactive epitope is a non-acidic O-linked carbohydrate or glycopeptide epitope with restricted expression in prostate carcinomas and bovine submaxillary glands. This expression is distinct from other mucin-like tumor-associated antigens identified in human prostate carcinomas.
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PMID:Characterization of a prostate carcinoma mucin-like antigen (PMA). 755 18

Serum resistance of gonococci in most patients is due to sialylation of a Gal beta 1-4GlcNAc group on a conserved 4.5 kDa lipopolysaccharide (LPS) component by host cytidine 5'-monophospho-N-acetyl neuraminic acid (CMP-NANA) catalysed by a gonococcal sialyl transferase. This sialylation is enhanced by a low M(r) factor(s) which, like CMP-NANA, is released in diffusates from high M(r) fractions obtained from sonicates dialysed at 4 degrees C. Also, as shown here, this factor(s) is released when the sonicates are dialysed at 18-20 degrees C. The enhancement of sialylation, first demonstrated using enzymes in gonococcal extracts, has been shown to occur in live gonococci and hence probably to have a role in pathogenicity. Gonococci, emerging from lag phase and incubated for 2 h with CMP-14CNANA fixed up to 90% more radiolabel than controls when the second factor(s) was present; their LPS separated by SDS-PAGE contained more radiolabel than control samples and label was not detected in any other component. Fractions with enhancing activity absorbed maximally at about 260 nm but a mixture of UDP-galactose (UDP-Gal), UDP-N-Acetyl galactosamine (UDP-GalNAc), UDP-glucose (UDP-Glc) and UDP-N-Acetyl glucosamine (UDP-GlcNAc) showed no significant enhancing activity. The enhancing action of the low M(r) fractions was unaffected by incubation with beta-galactosidase.
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PMID:Sialylation of lipopolysaccharide by CMP-NANA in viable gonococci is enhanced by low Mr material released from blood cell extracts but not by some UDP sugars. 783 May 28


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