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)

beta-D-galactosidase (beta-D-galactoside galactohydrolase, E.C. 3.2.1.23) activity was localised in the digestive tract of Setaria digitata. The enzyme extract shows maximum activity in the pH range between 3.5 and 5.0 and at 45 degrees C. The enzyme shows the Km value of 3.636 mM for the substrate 6-bromo-2-naphthyl beta-D-galactoside and Vmax of 28.57 nmol 6-bromo-2-naphthol liberated mg-1 protein min-1. Activation/inhibition of the enzyme by various ions, medicinal plants and drugs has been studied. Polyacrylamide gel electrophoresis revealed that the enzyme exists as single form. The medicinal plants and the drug filarin effectively inhibit the enzyme. The significance of these results are discussed in relation to chemotherapy.
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PMID:Some properties of beta-D-galactosidase from the adult filarial nematode Setaria digitata. 211 94

The chromosomal lac region of the coliform bacterium Klebsiella M5al was cloned into the multicopy plasmid pBR322 to give pHE7 and pHE8. pHE8 contains 12.6 kb of M5al DNA, including its complete lac operon, and pHE7 contains 2.5 kb of M5al DNA and includes the complete lac Y gene and a small segment of lacZ. The M5al operon has the same gene order as the Escherichia coli lac operon. The lac genes of the Lac plasmid of Klebsiella V9A were cloned into pBR322 to give pHE1 and pHE2, of approximately 39 and 43 kb. Both plasmids were unstable in an E. coli RecA-strain, in contrast to the stability of pHE8. Polyacrylamide gel electrophoresis tests suggested that the M5al beta-galactosidase monomer is about 5% longer, i.e. has about 50 more amino acids, than that of the E. coli Z gene. Tests made on the enzymes coded by the lac operons of M5al, another Klebsiella strain (V9A) and its resident Lac plasmid, and several Lac+ Enterobacteria, led to the conclusion that only Escherichia coli among the Enterobacteria contains an active lacA gene.
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PMID:Clonal analysis of the lac operons from Klebsiella M5al and the Lac plasmid (pRE2) from Klebsiella V9A. 251 12

The cationic form of beta-galactosidase (EC 3.2.1.23) from the germinating seeds of Vigna sinensis has been separated from its other isoforms by DEAE-cellulose (DE-52) column chromatography and further purified by gel filtration and affinity chromatography. Polyacrylamide gel electrophoresis of the purified enzyme imparted a single protein band. The molecular mass of the enzyme as determined by Sephadex G-150 gel filtration is 58,800 Da. The optimum temperature and the optimum pH are 60 degrees C and 4.5, respectively. Most of the metal ions tested were inhibitory to the enzyme activity. The enzyme has Km for p-nitrophenyl beta-D-galactoside and o-nitrophenyl beta-D-galactoside of 0.56 and 2.0 mM, respectively. The Ki values of galactose and lactose are 2.4 and 70.0 mM, respectively. The energy of activation of PNPG for the enzyme is 10.3 kcal/mol.
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PMID:Cationic form of beta-galactosidase in the germinating seeds of Vigna sinensis (Linn) Savi. 309 79

By chemoenzymatic synthesis the gene for a (Leu27) analogue of human growth hormone releasing hormone-Gly45 [(Leu27)GHRH-Gly45] was constructed, cloned and expressed in Escherichia coli as a fusion protein with beta-galactosidase under the control of the lac promoter and operator. Upon induction with isopropyl-D-thio-beta-galactopyranoside the fusion protein accumulated to a yield of 15-20% of the total cellular protein. After cyanogen bromide cleavage of the fusion protein the precursor peptide (Leu27)hGHRH-Gly45 was separated by extraction and purified by ion exchange and h.p.l.c.-RP18 chromatography. The purified peptide was analysed by sequencing, isoelectric focusing, amino acid analysis and amino acid analysis after V8 protease digestion. The carboxy-terminal glycine was subsequently amidated by PAM (peptidylglycine-alpha-amidating-monooxygenase), an enzyme which was isolated and characterized from fresh bovine pituitaries. Correct amidation of the penultimate amino acid, leucine, was verified by peptide sequencing with an authentic leucine amide reference.
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PMID:Enzymatic amidation of recombinant (Leu27) growth hormone releasing hormone-Gly45. 314 33

Many bioactive peptides terminate with an amino acid alpha-amide at their COOH terminus. The enzyme responsible for this essential posttranslational modification is known as peptidyl-glycine alpha-amidating monooxygenase or PAM. We identified cDNAs encoding the enzyme by using antibodies to screen a bovine intermediate pituitary lambda gt11 expression library. Antibodies to a beta-galactosidase/PAM fusion protein removed PAM activity from bovine pituitary homogenates. The 108,207 dalton protein predicted by the complete cDNA is approximately twice the size of purified PAM. An NH2-terminal signal sequence and short propeptide precede the NH2 terminus of purified PAM. The sequences of several PAM cyanogen bromide peptides were localized in the NH2-terminal half of the predicted protein. The cDNA encodes an additional 430 amino acid intragranular domain followed by a putative membrane spanning domain and a hydrophilic cytoplasmic domain. The forms of PAM purified from bovine neurointermediate pituitary may be generated by endoproteolytic cleavage at a subset of the 10 pairs of basic amino acids in the precursor. High levels of PAM mRNA were found in bovine pituitary and cerebral cortex. In corticotropic tumor cells, levels of PAM mRNA and pro-ACTH/endorphin mRNA were regulated in parallel by glucocorticoids and CRF.
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PMID:Structure of the precursor to an enzyme mediating COOH-terminal amidation in peptide biosynthesis. 315 62

1. Chicken brain arylsulphatase A was purified 2000-fold, with overall recovery 14%, by using ammonium sulphate fractionation, ethanol precipitation, Sephadex G-200 gel filtration and DEAE-Sephadex column chromatography. 2. The purified preparation was free from beta-glucuronidase, beta-galactosidase, acid phosphatase, inorganic pyrophosphatase and adenosine 3'-phosphate 5'-sulphatophosphate sulphohydrolase activities. 3. Polyacrylamide-gel electrophoresis indicated that the purified preparation was not homogeneous. 4. Chicken brain arylsulphatase was markedly inhibited by carbonyl reagents in the presence of traces of Cu(2+) in the system. Other metal ions such as Fe(2+) and Zn(2+), were inactive. 5. Ascorbic acid alone had no effect on enzyme activity but enhances the inhibition by Cu(2+). 6. Chicken brain arylsulphatase A resembled arylsulphatase A of other animal species in its kinetic properties such as K(m) value, anomalous time-activity relationship and the inhibitory effect of phosphate, sulphite and sulphate ions. However, its electrophoretic mobility, behaviour under zinc acetate fractionation and stimulation by Ag(+) were similar to arylsulphatase B of other animal species. Thus, this enzyme did not correspond to either arylsulphatase A or arylsulphatase B but properties of both. 7. The purified enzyme preparation can degrade cerebroside 3-sulphate.
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PMID:Purification and properties of arylsulphatase A from chicken brain. 507 33

Increased enterotoxigenicity of Vibrio cholerae 569B grown with low concentrations of lincomycin, previously described in terms of increased extracellular biological activity (capillary permeability factor and fluid accumulation in ligated rabbit ileal loops), was further characterized. Polyacrylamide gel electrophoresis and single radial immunodiffusion showed that lincomycin-stimulated cells produced increased molar quantities of cholera toxin (CT) both extra- and intracellularly. The intracellular CT was released in comparable amounts by sonication, deoxycholate extraction, and polymyxin B treatment. Polymyxin B release of CT was nearly complete under conditions wherein only 6% of total cellular beta-galactosidase was released, implying a periplasmic pool of CT in stimulated cells. No intracellular choleragenoid (CT subunit B) was found in stimulated cells by polymyxin B release. No proteolysis of 14C-labeled CT was detected after prolonged incubation with sonicated nonstimulated cultures or sonicated concentrated cells. These data support the conclusion that the stimulatory effect of lincomycin involves an increase in the rate of synthesis of the CT molecule, and argue against alternative models involving inhibition of putative normal degradation of CT, increased release of otherwise cell-bound CT, or activation of inactive, or less active, forms of CT.
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PMID:Lincomycin increases synthetic rate and periplasmic pool size for cholera toxin. 740 99

Native protein separations by capillary gel electrophoresis are achieved using linear acrylamide gel matrices. Polyacrylamide gels with a concentration range of 3.5-5% did not exhibit size separations for native proteins with molecular weights from 20,000 to 47,000. The separation of native proteins in gel-filled capillaries is based solely on the charge of the protein as in normal zonal electrophoresis. Retention of protein activity in the acrylamide matrix was demonstrated by performing enzymatic assays in the gel matrix. Alkaline phosphatase (ALP) and beta-galactosidase assays were conducted in both C18-PF108-modified and polyacrylamide gel-filled capillaries. Enzyme assays were achieved by filling the capillary with an appropriate substrate dissolved in the electrophoresis buffer. The product formed by the reaction of enzyme with substrate was monitored using a standard UV-visible detector. Both constant potential and zero potential modes of analysis were demonstrated. The polyacrylamide gel columns provide the advantages of minimized diffusion and limited band spreading due to the high viscosity of the gel matrix. The lowest detection limit achieved was 5.2 x 10(-20) mol (7.6 x 10(-12) M sample injected) of ALP. The dual enzyme assay of ALP and beta-galactosidase was achieved in gel-filled capillaries simultaneously.
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PMID:Native protein separations and enzyme microassays by capillary zone and gel electrophoresis. 837 67

The porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus. Virions of PRRSV contain six membrane proteins: the major proteins GP5 and M and the minor proteins GP2, GP3, GP4, and E. The GP5 is the major envelope proteins, which was involved in the formation and infectivity of PRRSV by coaction with other membrane proteins. Here, to determine the function of alone GP5 envelope protein in viral entry, we investigated the formation and infectivity of GP5-pseudotyped virus particles. By co-transfection of GP5 expression plasmids with murine leukemia virus (MuLV) based retroviral vectors (pHIT60, encoding MuLV Gag-Pol; pHIT111, encoding an MuLV genome with a beta-galactosidase reporter gene) into 293 T cells and analysis of the culture medium using ultracentrifugation, Western blot, and infection assay. We observed that the GP5 envelope protein was incorporated into the MuLV retroviral vectors to generate an pseudotyped murine leukemia virus, which was infectious to PAM and Mack-145 target cells and displayed the same host range with wild-type PRRSV. The infection of the pseudotyped virus on PAM target cells is effectively neutralized by polyclonal antibodies specific for PRRSV or GP5. The results suggested that the GP5 protein may play a key role in the viral entry by interacting with the host cell receptor. The GP5-pseudotyped virus will be useful in the identification of the cellular receptor binding with GP5 protein.
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PMID:Function of PRRSV GP5 envelope protein by using pseudotyped virus. 1947 88