Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: KEGG:D00046 (lactose)
16,692 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two toxic proteins were purified from the seeds of Abrus precatorius by DEAE-A 50 and Sepharose 4B chromatography. One of them does not bind on the Sepharose 4B column (Abrin-b) and the other (Abrin-a) is eluted with 0.2 M galactose. The amino acid compositions and tryptic maps of these two proteins were similar, but not identical. The molecular weights estimated by SDS-gel electrophoresis were 67,000 for abrin-b as compared with 65,000 for abrin-a. In the presence of mercaptoethanol, both abrin-a and abrin-b gave rise to two bands. The lethal doses of abrin-a and abrin-b for mice recorded within 48 h were 10 and 25 microgram per kg of body weight respectively. Abrin-a at 0.8 microgram per ml concentration level agglutinated human 0-type erythrocytes, whereas abrin-b showed no such activity. Abrin-a at 5 microgram per ml concentration level agglutinated both the Sarcoma 180 cells and Ehrlich ascites tumor cells, but it required 150 microgram per ml for abrin-b. Both these two proteins at a sublethal dose could inhibit the growth of Ehrlich ascites tumor cells which were injected simultaneously with these proteins. 131I-abrin-a and 131I-abrin-b were able to bind Sarcoma 180 cells, and the binding of abrin-a could be inhibited by lactose, raffinose, galactose and rhamnose, but none of 15 sugars tested inhibited the binding of abrin-b.
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PMID:Isolation of antitumor proteins abrin-A and abrin-B from Abrus precatorius. 74 90

Affinity labeling of rabbit IgG anti-lactose antibodies of restricted heterogeneity by bromacetylaminolac dye was carried out in dark and the label on the isolated chains determined by SDS gel electrophoresis. The pattern of labeling was compared with that obtained when the reaction was carried out in light using the same reagent. Differences were observed in the mode of labeling of chains. Possible use of mapping the active site of the antibody by the same labeling reagent which can exist in two geometrical forms under dark and light conditions is discussed.
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PMID:Affinity labeling of anti-lactose antibodies with bromoacetylaminolac dye in dark. 81 8

Cellobiose: quinone oxidoreductase was purified by ammonium sulfate precipitation, SP-Sephadex C-50 chromatography, and hydroxylapatite column chromatography. The purified enzyme is homogeneous by ultracentrifugal and SDS-gel electrophoretic analyses. The enzyme is a flavoprotein with FAD as the prosthetic group and produces cellobiono-delta-lactone as the product of cellobiose oxidation. Cellopentaose is also oxidized but no oxidation of cellulose could be detected. The enzyme oxidizes lactose and 4-beta-glucosylmannose but not 4-beta-mannosylglucose which implicates the C-2-hydroxyl of the non-reducing end of the disaccharide as important for substrate specificity.
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PMID:Purification and properties of cellobiose: quinone oxidoreductase from Sporotrichum pulverulentum. 115 54

Ductal infiltration carcinomas (d.i.c.) of the breast are potentially highly metastatic tumours, associated with drastic alterations of the architecture and molecular composition of the extracellular matrix at the tumour-host interface. 8701-BC, a recently characterized cell line, isolated from primary d.i.c., was used to study different aspects of tumor cell-substratum interactions. Since type V collagen deposition is augmented in d.i.c. we have examined the ability of 8701-BC cells to interact with this collagen species. We have found that cell binding to type V collagen was mediated by protein homologous to the 67 kDa laminin receptor (67-R). This conclusion is substantiated by the following observations: (a) a major band having an apparent molecular mass of 67 kDa and immunoreactive to the anti-67 R antibody was detectable by SDS-PAGE of the membrane proteins; (b) the antibody inhibited cellular adhesion to type V collagen in a dose-dependent way; (c) membrane proteins purified by affinity chromatography on type V collagen were immunoreactive to anti-67 R antibody, but not to anti-VLA1, VLA2 and VLA3 integrin antibodies. This receptor appears to have prominent carbohydrate-binding properties, since lactose competes with cell adhesion to type V collagen.
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PMID:Adhesion of 8701-BC breast cancer cells to type V collagen and 67 kDa receptor. 132 62

The surface antigens of Helicobacter pylori conferring erythrocyte-binding activity were obtained by adsorption onto formaldehyde-treated dog and goat erythrocytes from supernatant fractions of sonicated bacteria and elution using a high concentration of NaCl. The desorbed material was analysed by SDS-PAGE and immunoblotting with anti-whole-cell serum to agar-grown bacteria which had been absorbed with broth-grown, non-haemagglutinating cells (haemagglutination-associated antiserum). Two polypeptides with molecular masses of 25 and 59 kDa were revealed as erythrocyte-binding antigens. Strains which agglutinated both dog and goat erythrocytes possessed both these erythrocyte-binding antigens, whereas an antigenically cross-reactive 24 kDa polypeptide was present in a strain which only agglutinated goat erythrocytes. Haemagglutinin material was extracted from H. pylori using n-octylglucopyranoside and purified by Sepharose chromatography and sucrose density gradient ultracentrifugation. The purified extract directly agglutinated erythrocytes in a neuraminyl-lactose-sensitive and neuraminidase-sensitive manner. The 59 kDa polypeptide was not present in the purified haemagglutinin preparation. The haemagglutination-associated antiserum reacted strongly with the 25 kDa polypeptide band which was the most prominent polypeptide band on analysis of the purified haemagglutinin preparation by SDS-PAGE and silver staining. Thus, H. pylori possesses at least two adhesins, one of which recognises a N-acetylneuraminic acid (alpha 2-3) moiety of receptors, the other being of unknown receptor specificity. Differences in the antigenicity and molecular masses of these adhesins in individual strains may underlie differences in receptor-binding specificities and haemagglutination profiles.
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PMID:Identification of erythrocyte-binding antigens in Helicobacter pylori. 151 79

Piromyces sp. strain E2, an anaerobic fungus isolated from an Indian elephant (hindgut fermenter) was tested for its ability to ferment a range of substrates. The fungus was able to use bagasse, cellobiose, cellulose, fructose, glucose, lactose, mannose, starch, wheat bran, wheat straw, xylan and xylose. Formate and acetate were the main fermentation products after growth on these substrates. The amount of carbon found in the fermentation products of cultures, in which substrate digestion was complete averaged 88.5 mM, or 59% of the carbon offered as substrate. No growth was observed on other substrates tested. Lactose, starch, cellobiose and filter paper cellulose were good inducers of cellulolytic and xylanolytic enzymes. Cellulolytic and xylanolytic enzymes were produced constitutively by Piromyces strain E2, although enzyme activities were generally lower after growth on glucose and other soluble sugars. Complex substrates (bagasse, wheat bran, and wheat straw) were good inducers for xylanolytic enzymes but not for cellulolytic enzymes. The extracellular protein banding pattern after SDS-PAGE was therefore only slightly affected by the growth substrate. Identical beta-glucosidase and endoglucanase activity patterns were found after growth on different substrates. This indicated that differences in enzyme activities were not the result of secretion of different sets of isoenzymes although it remains possible that the relative amount of each isoenzyme produced is influenced by the growth substrate.
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PMID:Production of cellulolytic and xylanolytic enzymes during growth of the anaerobic fungus Piromyces sp. on different substrates. 152 5

Subcellular-fractionation techniques were used to characterize the endocytic pathway followed by ricin in rat liver in vivo and tentatively identify the site(s) at which the ricin interchain disulphide bridge is split. After injection of 125I-ricin, hepatic uptake of radioactivity was maximum at 30 min (40% of injected dose). At 5 min, about 80% of the radioactivity in the homogenate was recovered in the microsomal (P) fraction, but later on the recovery of the radioactivity in the mitochondrial-lysosomal (ML) fractions progressively increased (50% at 30 min) at the expense of that in the P fraction. Subfractionation of the P and ML fractions on analytical sucrose-density gradients revealed a time-dependent translocation of the radioactivity from low- to high-density endocytic structures, with median relative densities at 5 and 60 min of about 1.15 and 1.16 (P fraction) and 1.19 and 1.22 (ML fraction) respectively. The late distribution of the radioactivity in the ML fraction was similar to that of the lysosomal marker acid phosphatase. Studies with co-injected lactose and mannan showed that ricin was internalized mainly via the mannose receptor. In the presence of mannan, the late recovery of radioactivity in the ML fraction was decreased, and the distribution of the radioactivity associated with the P fraction was shifted toward lower densities (median relative density 1.13), indicating a different pathway of endocytosis. Analysis of the radioactivity associated with the ML and S fractions by SDS/PAGE revealed a time-dependent increase in the amount of intact A- and B-chains and low-molecular-mass products. When ML fractions containing partially processed ricin were incubated at 37 degrees C at pH 5 or at pH 7.2 in the presence of ATP, only low-molecular-mass products were generated. We conclude that internalized ricin associates with endocytic structures whose size and density of equilibration increase with time, and that, although detectable in these structures, reduction of the ricin interchain disulphide bridge occurs to a large extent in the cytosol.
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PMID:Uptake of injected 125I-ricin by rat liver in vivo. Subcellular distribution and characterization of the internalized ligand. 159 2

Lactose permease, the lacY gene product in Escherichia coli, is an integral membrane protein. Its induction was examined in secAts and secYts mutants by measuring o-nitrophenyl-beta-galactoside uptake activity. In contrast to the synthesis of the maltose binding protein, the malE gene product, which is dependent on the secA and secY gene products, lactose permease seemed to be produced and integrated functionally into membrane independently of SecA or SecY. Gene fusion of the lamB signal sequence to the N-terminal part of the lactose permease gene resulted in production of active fused permease in the E. coli membrane. The signal sequence did not seem to be processed, judging from its mobility on SDS polyacrylamide gel electrophoresis. E. coli cell growth was super-sensitive to induction of production of the fused permease with the signal sequence in contrast to induction of the normal lactose permease. These results are consistent with the above observation that production and integration of LacY protein into membrane is relatively independent of the SecY protein that may have a certain specificity for the signal sequence or, more generally, membrane translocation intermediates.
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PMID:Membrane assembly of lactose permease of Escherichia coli. 161 33

Shiga-like toxin (SLT)-I and SLT-II/IIc bound to Synsorbs containing synthetic alpha Gal(1-4)beta Gal (P1 disaccharide), alpha Gal(1-4)beta GlcNAc (P1 trisaccharide), or alpha Gal(1-4)beta Gal(1-4)beta Glc (Pk trisaccharide) sequences but not to Synsorbs containing alpha Gal(1-3)beta Gal, alpha Gal(1-3)beta Gal(1-4)beta GlcNAc, or the hydrophobic oligosaccharide linkage arm. SLT-I had a preference for Synsorbs containing trisaccharides, whereas SLT-II/IIc binding was less selective. 125I-labeled SLT-I remained bound to Pk trisaccharide Synsorb in the presence of lactose, galactose, or EDTA but was partially released by acetic acid, guanidine HCl, or a 10% solution of SDS. Vero cells coincubated with Pk trisaccharide Synsorb and SLT I extract were protected from this toxin, whereas Pk trisaccharide Synsorb was much less efficient at neutralizing SLT-II/IIc activity in Vero cell coincubation experiments. The SLT-IIc component was not responsible for the inefficient neutralization. Results suggest that synthetic oligosaccharide sequences related to the P blood group antigens coupled to inert matrices could be useful for rapid diagnosis or possibly therapeutic intervention in enterohemorrhagic Escherichia coli infections.
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PMID:Investigation of Shiga-like toxin binding to chemically synthesized oligosaccharide sequences. 165 99

Oral streptococci vary in their susceptibility to salivary agglutinin-mediated aggregation. To understand the molecular basis of this specificity, the structure and function of receptors for agglutinin from Streptococcus mutans KPSK2 (MSL-1) and Streptococcus sanguis M5 (SSP-5) were compared. Immunological screening of an S. mutans KPSK2 genomic DNA library yielded two identical clones expressing a streptococcal protein that co-migrated with a 220 kDa peptide in SDS extracts from this organism. This protein inhibited agglutinin-mediated aggregation of S. mutans KPSK2 in a dose-dependent manner. The MSL-1 gene is homologous to the S. mutans SpaP and pac genes although single base substitutions alter several amino acids. MSL-1 is also similar to the agglutinin receptor (SSP-5) cloned from S. sanguis M5. All three proteins, MSL-1, P1, and SSP-5 share at least one epitope since monoclonal and polyclonal anti-SSP-5 antibodies react with both MSL-1 and P1. However, other monoclonal antibodies are specific for SSP-5 and appear to react with a peptide domain exhibiting little homology to MSL-1 or P1. Sugar inhibition studies showed that agglutinin-mediated aggregation of S. mutans KPSK2 was most potently inhibited by fucose and lactose. Sialic acid, a potent inhibitor of S. sanguis aggregation, had no effect on the interaction of agglutinin with S. mutans KPSK2. These results suggest that while the MSL-1 and SSP-5 proteins are genetically and immunologically related, their specificity for binding sites on agglutinin differs.
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PMID:Comparison of Streptococcus mutans and Streptococcus sanguis receptors for human salivary agglutinin. 170 78


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