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)

Phosphatases, C4 and C8 esterases, leucine and valine aminopeptidases, n-acetyl-beta-glucosaminidase, beta-glucosidase, beta-galactosidase and beta-glucuronidase were active in extracts of scab mites (Psoroptes spp.) raised on sheep or rabbits. Trypsin and chymotrypsin activities were not detected. Haemoglobin was hydrolysed by a detergent-soluble fraction of the mite extracts in a pH-dependent fashion with an optimum of pH 3-5. Acid proteinase activity was greater in mites raised on rabbits than in those raised on sheep. Inhibitors of cysteine, serine and metallo-proteinases failed to inhibit the hydrolysis of H-Pro-Thr-Glu-Phe-Phe(NO2)Arg-Leu-OH while pepstatin A, a specific inhibitor of aspartic proteinases, totally inhibited its hydrolysis at a concentration of 1 nM.
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PMID:Immunological control of scab mites: digestive enzymes as candidate compounds. 1042 5

Human parvovirus B19 gene expression from the viral p6 promoter (B19p6) is restricted to primary human hematopoietic cells undergoing erythroid differentiation. We have demonstrated that expression from this promoter does not occur in established human erythroid cell lines in the context of a recombinant parvovirus genome (Ponnazhagan et al. J Virol 69:8096-8101, 1995). However, abundant expression from this promoter can be readily detected in primary human bone marrow cells (Wang et al. Proc Natl Acad Sci USA 92:12416-12420, 1995; Ponnazhagan et al. J Gen Virol 77:1111-1122, 1996). In the present studies, we investigated the pattern of expression from the B19p6 promoter in primary human bone marrow-derived CD34+ HPC undergoing differentiation into myeloid and erythroid lineages. CD34+ cells were transduced with recombinant adeno-associated virus 2 (AAV) vectors containing the beta-galactosidase (lacZ) gene under the control of the following promoters/enhancers: the cytomegalovirus promoter (vCMVp-lacZ), B19p6 promoter (vB19p6-lacZ), B19p6 promoter with an upstream erythroid cell-specific enhancer element (HS-2) from the locus control region (LCR) from the human beta-globin gene cluster (vHS2-B19p6-lacZ), and the human beta-globin gene promoter with the HS-2 enhancer (vHS2-beta p-lacZ). Transgene expression was evaluated either 48 h after infection or following erythroid differentiation in vitro for 3 weeks. Whereas high-level expression from the CMV promoter 48 h after infection diminished with time, low-level expression from the B19p6 and the beta-globin promoters increased significantly following erythroid differentiation. Furthermore, in HPC assays, there was no significant difference in the level of expression from the CMV promoter in myeloid or erythroid cell-derived colonies. Expression from the B19p6 and the beta-globin promoters, on the other hand, was restricted to erythroid cell colonies. These data further corroborate that the B19p6 promoter is erythroid cell-specific and suggest that the recombinant AAV-B19 hybrid vectors may prove useful in gene therapy of human hemoglobinopathies in general and sickle cell anemia and beta-thalassemia in particular.
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PMID:Adeno-associated virus 2-mediated transduction and erythroid lineage-restricted expression from parvovirus B19p6 promoter in primary human hematopoietic progenitor cells. 1064 62

Efficient binding of biomacromolecular surfaces by synthetic systems requires the effective presentation of complementary elements over large surface areas. We demonstrate here the use of mixed monolayer protected gold clusters (MMPCs) as scaffolds for the binding and inhibition of chymotrypsin. In these studies anionically functionalized amphiphilic MMPCs were shown to inhibit chymotrypsin through a two-stage mechanism featuring fast reversible inhibition followed by a slower irreversible process. This interaction is very efficient, with a K(i)(app) = 10.4 +/- 1.3 nM. The MMPC-protein complex was characterized by CD, demonstrating an almost complete denaturation of the enzyme over time. Dynamic light scattering studies confirm that inhibition proceeds without substantial MMPC aggregation. The electrostatic nature of the engineered interactions provides a level of selectivity: little or no inhibition of function was observed with elastase, beta-galactosidase, or cellular retinoic acid binding protein.
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PMID:Inhibition of chymotrypsin through surface binding using nanoparticle-based receptors. 1192 86

The Escherichia coli cAMP receptor protein (CRP) displays biphasic characteristics in protease and beta-galactosidase induction assays at increasing cAMP concentrations in response to ligand binding at the secondary binding site located between the primary binding site and the DNA binding domain. Two mutants were created to determine the mechanistic reason for the CRP biphasic response by inhibiting binding of cAMP to the secondary site via interference with the Arg 181 interaction with the ligand's phosphate. The S179A/R180D/E181H mutant binds two cAMP molecules per dimer, does not exhibit a biphasic response, lacks selective DNA binding, and has inhibited nonselective DNA binding. The R180K mutant binds four cAMP molecules per dimer, exhibits a biphasic response, nonselective DNA binding similar to CRP, but has inhibited selective DNA binding characteristics. The results are consistent with a 2 x 2-binding site scheme were both primary binding sites must be occupied before the secondary binding sites are occupied. A structural mechanism suggesting the secondary sites are formed by binding of cAMP to the primary sites is proposed. AMMP-generated molecular models suggest that R180 orients E181 to produce selective DNA binding, Arg 169 interactions are necessary for nonselective DNA binding, and the position of Leu 57 inhibits chymotrypsin cleavage of Phe 136. DNA binding results suggest that CRP may be the unknown transcription factor which binds to the temperature sensitive dsrA promoter.
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PMID:Proposed structural mechanism of Escherichia coli cAMP receptor protein cAMP-dependent proteolytic cleavage protection and selective and nonselective DNA binding. 1595 80

Often used to remove sulfate groups from carbohydrates, the regulatory properties of the aryl sulfatase from Helix pomatia remain little characterized. As many hydrolytic enzymes utilize exogenous metal ions in catalysis, the effect of various divalent metal ions on the sulfatase was investigated. Evidence for metal ion activation was collected, with Cd(2+) being notable for effective activation. The enzyme was inhibited by Cu(2+). The response of other common hydrolases to divalent metal ions was characterized. Activation by Cd(2+) was not observed for chymotrypsin, rabbit liver esterase, or beta-galactosidase. Instead, Cd was found to inhibit both the esterase and the galactosidase. Inhibition by Cu(2+) and Zn(2+) was also observed for some of these hydrolases.
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PMID:Evidence for the Cd(2+) activation of the aryl sulfatase from helix pomatia. 1633 54

Directed endodermal differentiation of murine embryonic stem (ES) cells gives rise to a subset of cells with a hepatic phenotype. Such ES cell-derived hepatic progenitor cells (ES-HPC) can acquire features of hepatocytes in vitro, but fail to form substantial hepatocyte clusters in vivo. In this study, we investigated whether this is due to inefficient engraftment or an immature phenotype of ES-HPC. ES cells engrafted into recipient livers of NOD/SCID mice with a similar efficacy as adult hepatocytes after 28 days. Because transplanted unpurified ES-HPC formed teratomas in the spleen and liver, we applied an albumin promoter/enhancer-driven reporter system to purify ES-HPC by cell sorting. RT-PCR analyses for hepatocyte-specific genes showed that the cells exhibited a hepatic phenotype, lacking the expression of the pluripotency marker Oct4, comparable to cells of day 11.5 embryos. Sorted ES-HPC derived from beta-galactosidase transgenic ES cells were injected into fumaryl-acetoacetate-deficient (FAH(-/-)) SCID mice and analyzed after 8 to 12 weeks. Staining with X-gal solution revealed the presence of engrafted cells throughout the liver. However, immunostaining for the FAH protein indicated hepatocyte formation at a very low frequency, without evidence for large hepatocyte cluster formation. In conclusion, the limited repopulation capacity of ES-HPC is not caused by a failure of primary engraftment, but may be due to an immature hepatic phenotype of the transplanted ES-HPC.
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PMID:Murine embryonic stem cell-derived hepatic progenitor cells engraft in recipient livers with limited capacity of liver tissue formation. 1852 34

The purpose of this study was to evaluate the effect of high hydrostatic pressure (HHP) on the enzyme activities in Saccharomyces cerevisiae (ATCC 16664) and Escherichia coli (ATCC 11229). Enzyme activities before and after HHP treatment were determined using an APIZYME enzyme assay kit. Thirteen active enzymes were detected in S. cerevisiae and E. coli. Pressure treatment at 448 MPa for 30s at 23 degrees C resulted in different effects on enzymes in S. cerevisiae and E. coli. HHP completely inactivated lipase, cystine arylamidase, and chymotrypsin and moderately inactivated esterase, esterase lipase, leucine arylamidase, valine arylamidase and alpha-glucosidase in S. cerevisiae. In E. coli, esterase, esterase lipase, lipase, valine arylamidase, cystine arylamidase, trypsin, alpha-glucosidase, and beta-glucuronidase were completely inactivated and leucine arylamidase and beta-galactosidase retained partial activities. Phosphoric hydrolases were not inactivated in both microorganisms. The use of the enzyme assay kit provided rapid and useful information on the microorganisms' enzymes and their sensitivity to HHP treatment in a simple manner.
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PMID:Effect of high hydrostatic pressure on the enzyme activities in Saccharomyces cerevisiae and Escherichia coli. 2021 5


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