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-Galactosidase and other enzymes were immobilized on p-amino-carbanilated derivatives of cellulose and methylol cellulose using the diazo method and through glutaraldehyde. The optimum conditions for coupling cellulose tri-(p-amino-carbanilate) (CTAC) to beta-galactosidase were established. The diazo coupling method with CTAC gave greater activity than with glutaraldehyde when coupled to beta-galactosidase (Escherichia coli). The stability of the CTAC-beta--galactosidase system was examined. The disubstituted p-amino-carbanilate derivative (CDAC) gave a lower activity, whereas the methylol analog (MCTAC) gave slightly greater activity. The CTAC was also used to immobilize glucose oxidase, trypsin, pepsin, and papain.
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PMID:Immobilization of beta-galactosidase and other enzymes onto p-amino-carbanilated cellulose derivatives. 676 31

A method is described for coupling enzymes to immunoglobulins using sulphydryl derivatives of the proteins and a dimaleimide which is relatively water-soluble. Parameters affecting the performance of the conjugates have been examined including level of sulphydryl incorporation, ratio of enzyme/immunoglobulin and nature of dimaleimide used. Peroxidase-immunoglobulin conjugates made by the dimaleimide method have been compared with those made by the periodate oxidation method and found to have a superior performance. Immunoglobulin has been linked to peroxidase (horseradish peroxidase, EC 1.11.1.7), glucose oxidase from Aspergillus niger, (EC 1.1.3.4), penicillinase from Bacillus cereus beta-lactamase I (EC 3.5.2.6), and beta-galactosidase from Escherichia coli (EC 3.2.1.23).
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PMID:Conjugation of enzymes to immunoglobulins using dimaleimides. 698 11

Enzyme selection is very important to establish enzyme immunoassay system. The appropriate enzyme selected to label an immunochemical reagent must have certain qualities as follows: 1) highly purified and high specific activity, 2) inexpensive, 3) stable during conjugation and for a long time in a proper storage condition, 4) easily conjugated, measured, and applied to highly sensitive assay. Several enzymes fulfill most of the above requirements and have been successfully used in enzyme immunoassay. These are horseradish peroxidase, alkaline phosphatase, beta-galactosidase, glucose oxidase, glucose-6-phosphate dehydrogenase, etc. As for enzyme activity measuring procedures, chemiluminescence and bioluminescence assays generally exhibit more sensitive detection limits than fluorescent or colorimetric assays. In the future, ultrasensitive luminescent assays and production of excellent recombinant enzymes are expected.
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PMID:[Properties of enzymes for enzyme immunoassay]. 747 74

We discuss, from an industrial point of view, the scope and possibilities of recombinant DNA technology for "diagnostic enzyme" production and application. We describe the construction of enzyme-overproducing strains and show how to simplify downstream processing, increase product quality and process profitability, improve diagnostic enzyme properties, and adjust enzymes to harsh assay conditions. We also consider some safety and environmental aspects of enzyme production. Other aspects of diagnostic enzymes that we cover are the facilitation of enzyme purification by attachment of short amino acid tails, the introduction of tails or tags for site-specific conjugation or oriented immobilization, the construction of bi- or multifunctional enzymes, and the production of enzyme-based diagnostic tests as demonstrated by the homogeneous immunoassay system of CEDIA tests. We use as examples of diagnostic enzymes glucose-6-phosphate dehydrogenase (EC 1.1.1.49), glucose oxidase (EC 1.1.3.4), alkaline phosphatase (EC 3.1.3.1), alpha-glucosidase (EC 3.2.1.20), pyruvate oxidase (EC 1.2.3.3), creatinase (EC 3.5.3.3), and beta-galactosidase (EC 3.2.1.23).
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PMID:Enzymes in diagnostics: achievements and possibilities of recombinant DNA technology. 817 39

A sandwich-type flow-injection binding assay for quantitation of various IgG's was developed. The assay is based on the pseudoimmunological reaction between protein A from Staphylococcus aureus and immunoglobulin G from different species. Protein A immobilized on a solid support and a fusion protein of protein A and beta-galactosidase from Escherichia coli are used for detection. The fusion protein is produced with a temperature-inducible recombinant E. coli strain. A sandwich is formed by subsequent injection of IgG and fusion protein into the buffer stream flowing through the immobilized protein A column. The amount of enzyme activity bound is proportional to the amount of IgG bound and is measured by pumping a lactose solution as substrate for beta-galactosidase through the protein A column. Lactose is converted to glucose and galactose. The detector is an enzyme thermistor that measures the heat evolved in the enzymatic conversion of glucose by coimmobilized glucose oxidase and catalase. The assay takes 16 min at a flow rate of 0.6 mL min-1 with a lower detection limit of 33 pmol per injection of rabbit IgG. The precision of replicate measurements has a standard deviation of 4-5%, and the column can be used for more than 50 cycles.
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PMID:Specific flow injection sandwich binding assay for IgG using protein A and a fusion protein. 829 25

Tissue-specific delivery of variety of molecules has been a valuable technique for biological and medical research and for the diagnosis and therapy of cancer. We have therefore examined the ability of streptavidin-protein A (ST-PA) fusion protein complexed with monoclonal antibodies (mAbs) to transfer biotinylated proteins into specific type of cells. ST-PA/mAbs complexes could efficiently deliver biotinylated beta-galactosidase into a variety of cancer cell lines through molecules expressed on their surface. In addition, ST-PA/mAb complexed with either biotinylated glucose oxidase or biotinylated ribonuclease A could be transferred to specific cell types and made to display cytotoxic activity against the transduced cell. The flexibility of the system was enhanced by the fact that the cell-targeting specificity could be altered by just changing the mAb used and the "payload" molecule could be replaced by substituting one biotinylated protein or enzyme with another. This flexibility was achieved without the need to generate a covalent chemical link or engineering new recombinant molecules. Results obtained to date suggest that the ST-PA fusion protein may be used as a nearly "universal carrier" to transfer a variety of effector molecules into target cells with a high degree of specificity. Essentially, the ST-PA fusion protein effectively serves as a high-efficiency, modular "molecular bridge" for the transfer into cells of a wide variety of effector molecules.
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PMID:Cell-specific, multidrug delivery system using streptavidin-protein A fusion protein. 881 44

Tissue-specific delivery of a variety of molecules has been a valuable technique for biological and medical research. Therefore, we have constructed a recombinant plasmid containing the coding regions for streptavidin core and mature human transforming growth factor-alpha (TGF-alpha). The recombinant plasmid has been expressed in Escherichia coli to produce a chimeric protein with both streptavidin and TGF-alpha activity. The streptavidin-TGF-alpha chimeric protein (ST-TGF-alpha) could efficiently transfer biotinylated beta-galactosidase into A431 cells via the epidermal growth factor receptor. More than 99% of the cells contained the enzyme transferred. Furthermore, ST-TGF-alpha complexed with biotinylated-glucose oxidase had a significant cytotoxic effect when incubated with A431 cells. These findings suggest that the ST-TGF-alpha chimeric protein could be used to deliver proteins of interest into target cells without the need for chemical linkage or genetic construction. Essentially, ST-TGF-alpha serves as a high-modular "molecular bridge" for the passage of a wide variety of effector molecules into target cells.
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PMID:Multi-drug delivery system using streptavidin-transforming growth factor-alpha chimeric protein. 892 14

New modalities of treatment for small-cell lung cancer (SCLC) are needed, because the majority of patients continue to die of disseminated disease despite an initial response to conventional chemotherapy. Abnormal surface expression of the neural-cell adhesion molecule (NCAM) has been noted to be highly associated with SCLC. We examined the ability and efficiency of a streptavidin-Protein A (ST-PA) fusion protein complexed with an anti-NCAM monoclonal antibody (Mab) to transfer biotinylated beta-galactosidase into human SCLC cell lines NCI-H69, NCI-H526, and NCI-H446. When the surface molecule NCAM was targeted with this system, more than 99% of the targeted cells internalized and exhibited beta-galactosidase activity. In addition, we evaluated cytotoxic activity against SCLC lines NCI-H69 and NCI-H526 by efficient delivery of biotinylated glucose oxidase using the same ST-PA/anti-NCAM Mab complex. Cytotoxicity of the transduced cells (SCLC) was 10-fold and 100-fold greater, respectively, than the glucose oxidase control. This system could be widely applied for specific therapy of cancer cells by targeting unique surface molecules (antigens) using the corresponding Mab/ST-PA complex to transfer a variety of effector molecules; e.g., immunotoxic compounds, into target cells with a high degree of efficiency and specificity.
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PMID:Specific cell targeting for delivery of toxins into small-cell lung cancer using a streptavidin fusion protein complex. 1094 28

Two types of amperometric biosensors for lactose detection based either on co-immobilisation of two enzymes (galactose oxidase with peroxidase) or co-immobilisation of three enzymes (beta-galactosidase, galactose oxidase and peroxidase) were constructed. A graphite rod with pre-adsorbed ferrocene was used as a working electrode. The use of galactose oxidase instead of the frequently used glucose oxidase resulted in the construction of a glucose-non-interfering lactose sensor. Co-immobilisation of peroxidase with galactose oxidase allowed the effect of borate on the extension of the linear range and the effect of the working potential on galactose oxidase activation to be studied. The presence of beta-galactosidase greatly enhances the sensor's sensitivity, but its linear range is narrower than that of the sensor without beta-galactosidase. Addition of DEAE-dextran and inositol to the enzyme layer improved the half-life more than 16-fold compared with the sensor without stabilisers. A response time between 60 and 75 s (90% of the steady-state value) and a detection limit for lactose determination from 44 to 339 microM (signal-to-noise ratio = 3) were observed depending on the conditions. The precision of measurements of standard lactose solution for the trienzymatic and bienzymatic sensors was 2.19 and 2.02%, respectively. The precision of analysis of dairy products varied from 0.24 to 5.24%. Analyses of real samples showed good correlation with HPLC analysis; eight samples and 10 standard lactose solutions without pre-treatment were analysed in 1 h.
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PMID:Novel glucose non-interference biosensor for lactose detection based on galactose oxidase-peroxidase with and without co-immobilised beta-galactosidase. 1098 24

The increasing demand for on-line measurement of milk composition directs science and industry to search for practical solutions, and biosensors may be a possibility. The specific objective of this work was to develop an electrochemical biosensor to determine lactose concentration in fresh raw milk. The sensor is based on serial reactions of three enzymes--beta-galactosidase, glucose oxidase, and horseradish peroxidase--immobilized on a glassy carbon electrode. The sequential enzymatic reactions increase the selectivity and sensitivity of the sensor. The sensor requires dilution of the raw milk and the addition of 5-aminosalicylic acid. Lactose concentrations in raw milk measured by the sensor were in good agreement with those measured by a reference laboratory using infrared technology. The results were obtained in milk samples that varied in fat and protein composition. From the results, we conclude that an electrochemical biosensor for determination of lactose concentration in fresh raw milk can be developed, and that the biosensor presented in this study maintained the qualities required for further development into an online sensor in the milking parlor.
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PMID:A three-cascaded-enzymes biosensor to determine lactose concentration in raw milk. 1100 21


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