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)

When strains of Escherichia coli K12 and Salmonella spp. were incubated with 0.5-0.7 mol/l formic or propionic acid at pH 5.0, propionic acid was more active than formic acid. It killed 90% of the cell population within 60 min compared with over 3 h for formic acid. Cell death was not associated with a reduction in culture turbidity or a loss of membrane integrity since morphologically normal membranes were observed by electron microscopy and only a small proportion of the cytoplasmic enzyme beta-galactosidase leaked into the supernatant fluid of acid-treated E. coli K12 cultures.
 ...
PMID:Short-chain organic acids at ph 5.0 kill Escherichia coli and Salmonella spp. without causing membrane perturbation. 190 5

A novel monosialoganglioside was isolated from Tay-Sachs brains. It represented about 0.1% of the total ganglioside mixture. Compositional analysis by gas-liquid chromatography indicated that it contained glucose, galactose, N-acetylgalactosamine, N-acetylneuraminic acid, and long chain base in the molar ratio of 1:2:2:1:1. The ganglioside was found to be resistant to neuraminidase (Clostridium perfringens), beta-hexosaminidase (jack bean), and beta-galactosidase. However, it could be degraded by a human liver beta-hexosaminidase preparation in the presence of an activator to produce a glycolipid chromatographically identical with authentic IV3NeuAc-GgOse4-ceramide. This glycolipid product was resistant to beta-galactosidase (jack bean), but could be readily degraded to GgOse4-ceramide by neuraminidase. Mild formic acid hydrolysis degraded the intact ganglioside to an asialo derivative chromatographically identical with the pentahexosyl ceramide (GalNAc-Gal-GalNAc-Gal-Glc-ceramide) derived from GD1a-GalNAc. The asialo derivative could then be degraded to GgOse4-ceramide and GgOse3-ceramide by sequential treatment with jack bean beta-hexosaminidase and beta-galactosidase. These data suggest that the novel ganglioside is a monosialosylpentahexosyl ceramide with the sialosyl group attached to the penultimate galactose moiety of the pentahexosyl ceramide backbone, and it has the following structure: GalNAc(beta 1-4)Gal(beta 1-3)GalNAc(beta 1-4)Gal(beta 1-4)Glc-ceramide (formula see text).
 ...
PMID:Isolation and characterization of a novel monosialosylpentahexosyl ceramide from Tay-Sachs brain. 745 32

To examine whether the epidermal growth factor (EGF)-like domain Pro47-Asp87 is involved in the interaction of tissue plasminogen activator (t-PA) with platelets, we have expressed this domain in E. coli. The peptide fragment was produced from a plasmid expression vector as a fusion protein with beta-galactosidase Met1-Val444 at high yield in eight clones of E. coli. The fusion protein was purified and subjected to mild acid hydrolysis with formic acid, then the peptide Pro47-Asp87, identified by immunoblotting using specific antibodies to t-PA, was isolated by HPLC. After incubation with blood platelets spin labelled with 16-doxylstearic acid or 5-doxylstearic acid, the Pro47-Asp87 peptide fragment reduced fluidity of the membrane lipid bilayer to the same extent as did intact t-PA as indicated by ESR measurements. Our data suggest that the EGF-like domain of t-PA can directly interact with blood platelets and thus it seems to contain those sites of the t-PA molecule that bind the platelet membrane components.
 ...
PMID:The epidermal growth factor-like domain from tissue plasminogen activator. Cloning in E. coli, purification and ESR studies of its interaction with human blood platelets. 803 Mar 71

The epitope of a monoclonal antibody specific for the alpha 2 isoform of the Na,K-ATPase was determined and its accessibility in native enzyme was examined. Protein fragmentation with N-chlorosuccinimide, formic acid, trypsin, and leucine aminopeptidase indicated binding near the Na,K-ATPase N-terminus but did not unambiguously delineate the extent of the epitope. The ability of the antibody to bind to denatured enzyme made it a good candidate for screening a random peptide library displayed on M13 phage, but the consensus sequence that emerged was not found in the Na,K-ATPase, Full-length cDNA for the Na,K-ATPase was randomly fragmented and cloned into beta-galactosidase to create a lambda gt11 expression library; screening with the antibody yielded a set of overlaps spanning 23 amino acids at the N-terminus. Chimeras of Na,K-ATPase alpha 1 and alpha 2 narrowed down the epitope to 14-19 amino acids. The antibody did not recognize fusion proteins constructed with shorter segments of this epitope. It did recognize a fusion protein containing the M13 library consensus sequence, however, indicating that this sequence, which is rich in proline and hydrophobic amino acids (FPPNFLFPPPP), was a mimotope. The natural epitope, unique to the Na,K-ATPase alpha 2 isoform, was GREYSPAATTAENG. Reconstitution of antibody binding in a foreign context such as M13 PIII protein or beta-galactosidase thus required a relatively large number of amino acids, indicating that antibody mapping approaches must allow for epitopes of significant size. The epitope was accessible in native enzyme and exposed on the cytoplasmic side, documenting the surface exposure of a stretch of amino acids at the N-terminus, where the Na,K-ATPase isoforms differ most.
 ...
PMID:Epitope and mimotope for an antibody to the Na, K-ATPase. 923 55

We find that peptides containing -Asn-Gly- sequences typically show approximately 70-80% degree of deamidation after standard overnight (approximately 12 h) tryptic digestion at 37 degrees C. This emphasizes the need for more detailed information about the deamidation reaction in -Asn-Gly- sequences, in which two deamidated species are produced, one containing an aspartic acid (-Asp-Gly-) residue and the other containing an isoaspartic acid (-betaAsp-Gly-) residue. For the peptide SLNGEWR (54-60 beta-galactosidase, E. coli), all three components of the reaction mixture were separated by HPLC on C18 300-A sorbent, with trifluoroacetic acid as an ion-pairing modifier. Their intensity ratios suggested the elution order -betaAsp-/-Asn-/-Asp-, which was subsequently confirmed by MALDI MS and MS/MS analysis. The kinetics of the deamidation was studied in detail for the synthetic SLNGEWR parent using RP HPLC with UV detection. The half-life of this peptide was found to be approximately 8 h under digestion conditions. Analysis of a large pool of peptide retention data shows that the -betaAsp-/-Asn-/ -Asp- retention order is normally observed under the above conditions, especially if the original -NG- sequence is surrounded by hydrophobic amino acids. However, changing chromatographic conditions to 100-A pore size sorbents, or using formic acid as a modifier, increases the retention time of -betaAsp- relative to the -Asn-/-Asp- pair, so the order can sometimes be different.
 ...
PMID:Deamidation of -Asn-Gly- sequences during sample preparation for proteomics: Consequences for MALDI and HPLC-MALDI analysis. 1697 Mar 46