The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform
Douglas D Anspaugh - One of the best experts on this subject based on the ideXlab platform.
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assays for the classification of two types of esterases carboxylic ester hydrolases and phosphoric triester hydrolases
Current protocols in immunology, 2002Co-Authors: Douglas D AnspaughAbstract:Assays for the Classification of Two Types of Esterases: Carboxylic Ester Hydrolase and Phosphoric Triester Hydrolase (Douglas D. Anspaugh and Michael Roe, North Carolina State University, Raleigh, North Carolina). This unit describes assays that quantitate two types of esterase the carboxylic ester hydrolases and the phosphoric triester hydrolases. Carboxylic ester hydrolases include the B-esterases, which are inhibited by organophosphorus compounds. Among the phosphoric triester hydrolases is aryldialkylphosphatase, which has been called A-esterase or paraoxonase due to its ability to oxidize paraoxon and other organophosphates. These assays are colorimetric and miniaturized for rapid simultaneous testing of multiple, small-volume samples in a microtiter plate format. There is also a discussion of the history of esterase nomenclature and the reasons why this large group of enzymes is so difficult to classify.
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Current Protocols in Toxicology - Assays for the Classification of Two Types of Esterases: Carboxylic Ester Hydrolases and Phosphoric Triester Hydrolases
Current protocols in immunology, 2002Co-Authors: Douglas D AnspaughAbstract:Assays for the Classification of Two Types of Esterases: Carboxylic Ester Hydrolase and Phosphoric Triester Hydrolase (Douglas D. Anspaugh and Michael Roe, North Carolina State University, Raleigh, North Carolina). This unit describes assays that quantitate two types of esterase the carboxylic ester hydrolases and the phosphoric triester hydrolases. Carboxylic ester hydrolases include the B-esterases, which are inhibited by organophosphorus compounds. Among the phosphoric triester hydrolases is aryldialkylphosphatase, which has been called A-esterase or paraoxonase due to its ability to oxidize paraoxon and other organophosphates. These assays are colorimetric and miniaturized for rapid simultaneous testing of multiple, small-volume samples in a microtiter plate format. There is also a discussion of the history of esterase nomenclature and the reasons why this large group of enzymes is so difficult to classify.
Cormac G M Gahan - One of the best experts on this subject based on the ideXlab platform.
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Bile Salt Hydrolase Activity in Probiotics Bile Salt Hydrolase Activity in Probiotics
Applied and Environmental Microbiology., 2006Co-Authors: Máire Begley, Colin Hill, Cormac G M GahanAbstract:Probiotics are defined as “living microorganisms, which upon ingestion in certain numbers exert health benefits on the host beyond inherent basic nutrition” (43). Various studies have indicated that probiotics may alleviate lactose intolerance; have a positive influence on the intestinal flora of the host; stimulate/modulate mucosal immunity; reduce inflammatory or allergic reactions; reduce blood cholesterol; possess anti-colon cancer effects; reduce the clinical manifestations of atopic dermatitis, Crohn’s disease, diarrhea, constipation, candidiasis, and urinary tract infections; and competitively exclude pathogens (35, 67, 75, 80, 99). Considering this impressive list of potential health-promoting benefits, it is not surprising that there continues to be considerable interest in the use of probiotics as biotherapeutic agents (67, 75, 82). Furthermore, given a heightened awareness among consumers of the link between diet and health and the fact that probiotic-containing foods are generally perceived as “safe” and “natural,” the global market for such foods is on the increase, particularly dairy-based products marketed for the prophylaxis or alleviation of gastrointestinal disorders (84). The selection of potential probiotic strains that would be capable of performing effectively in the gastrointestinal tract is a significant challenge. Strain selection has generally been based on in vitro tolerance of physiologically relevant stresses: e.g., low pH, elevated osmolarity, and bile (26, 53, 77, 100). In addition to these physiological assays, molecular investigations are now under way to determine the genetic basis of gastric survival and functionality (11, 78, 79) and inclusion of molecular markers identified by this approach into screening programs may lead to more well-defined and reliable results. The ability of probiotic strains to hydrolyze bile salts has often been included among the criteria for probiotic strain selection, and a number of bile salt hydrolases (BSHs) have been identified and characterized. However, microbial BSH activity has also been mooted to be potentially detrimental to the human host, and thus it is as yet not completely clear whether BSH activity is in fact a desirable trait in a probiotic bacterium. We review here the available literature on the reaction catalyzed by BSH enzymes, explore the ecological significance of BSH production, and briefly examine the impact that bile hydrolysis may have on human physiology. We conclude with suggestions for future work and possible applications of BSH research.
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Bile salt hydrolase activity in probiotics
Applied and Environmental Microbiology, 2006Co-Authors: Máire Begley, Colin Hill, Cormac G M GahanAbstract:Probiotics are defined as “living microorganisms, which upon ingestion in certain numbers exert health benefits on the host beyond inherent basic nutrition” (43). Various studies have indicated that probiotics may alleviate lactose intolerance; have a positive influence on the intestinal flora of the host; stimulate/modulate mucosal immunity; reduce inflammatory or allergic reactions; reduce blood cholesterol; possess anti-colon cancer effects; reduce the clinical manifestations of atopic dermatitis, Crohn’s disease, diarrhea, constipation, candidiasis, and urinary tract infections; and competitively exclude pathogens (35, 67, 75, 80, 99). Considering this impressive list of potential health-promoting benefits, it is not surprising that there continues to be considerable interest in the use of probiotics as biotherapeutic agents (67, 75, 82). Furthermore, given a heightened awareness among consumers of the link between diet and health and the fact that probiotic-containing foods are generally perceived as “safe” and “natural,” the global market for such foods is on the increase, particularly dairy-based products marketed for the prophylaxis or alleviation of gastrointestinal disorders (84). The selection of potential probiotic strains that would be capable of performing effectively in the gastrointestinal tract is a significant challenge. Strain selection has generally been based on in vitro tolerance of physiologically relevant stresses: e.g., low pH, elevated osmolarity, and bile (26, 53, 77, 100). In addition to these physiological assays, molecular investigations are now under way to determine the genetic basis of gastric survival and functionality (11, 78, 79) and inclusion of molecular markers identified by this approach into screening programs may lead to more well-defined and reliable results. The ability of probiotic strains to hydrolyze bile salts has often been included among the criteria for probiotic strain selection, and a number of bile salt hydrolases (BSHs) have been identified and characterized. However, microbial BSH activity has also been mooted to be potentially detrimental to the human host, and thus it is as yet not completely clear whether BSH activity is in fact a desirable trait in a probiotic bacterium. We review here the available literature on the reaction catalyzed by BSH enzymes, explore the ecological significance of BSH production, and briefly examine the impact that bile hydrolysis may have on human physiology. We conclude with suggestions for future work and possible applications of BSH research.
Maria Hrmova - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of (1,4)-β-D-mannans in barley ( Hordeum vulgare L.) is mediated by the concerted action of (1,4)-β-D-mannan endohydrolase and β-D-mannosidase
Biochemical Journal, 2007Co-Authors: Rachel a. Burton, Jelle Lahnstein, Geoffrey b. Fincher, Peter Biely, Maria HrmovaAbstract:A family GH5 (family 5 glycoside hydrolase) (1,4)-beta-D-mannan endohydrolase or beta-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pI of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K(m) constants of 0.16 mg x ml(-1) and 5.3 mM and kcat constants of 12.9 and 3.9 s(-1) respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-beta-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-beta-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-beta-D-manno-oligosaccharides to Man is a family GH1 beta-D-mannosidase, now designated HvbetaMANNOS1, but previously identified as a beta-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) beta-D-mannoside three times faster than 4NP beta-D-glucoside, and has an action pattern typical of a (1,4)-beta-D-mannan exohydrolase.
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Hydrolysis of (1,4)-β-D-mannans in barley (Hordeum vulgare L.) is mediated by the concerted action of (1,4)-β-D-mannan endohydrolase and β-D-mannosidase
Biochemical Journal, 2006Co-Authors: Maria Hrmova, Jelle Lahnstein, Rachel A Burton, Peter Biely, Geoffrey b. FincherAbstract:A family GH5 (family 5 glycoside hydrolase) (1,4)-β-D-mannan endohydrolase or β-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pi of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K m constants of 0.16 mg · ml -1 and 5.3 mM and k cat constants of 12.9 and 3.9 s -1 respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-β-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-β-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-β-D-manno-oligosaccharides to Man is a family GH1 β-D-mannosidase, now designated HvaβMANNOS1, but previously identified as a β-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) β-D-mannoside three times faster than 4NP β-D-glucoside, and has an action pattern typical of a (1,4)-β-D-mannan exohydrolase. © 2006 Biochemical Society.
Geoffrey b. Fincher - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of (1,4)-β-D-mannans in barley ( Hordeum vulgare L.) is mediated by the concerted action of (1,4)-β-D-mannan endohydrolase and β-D-mannosidase
Biochemical Journal, 2007Co-Authors: Rachel a. Burton, Jelle Lahnstein, Geoffrey b. Fincher, Peter Biely, Maria HrmovaAbstract:A family GH5 (family 5 glycoside hydrolase) (1,4)-beta-D-mannan endohydrolase or beta-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pI of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K(m) constants of 0.16 mg x ml(-1) and 5.3 mM and kcat constants of 12.9 and 3.9 s(-1) respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-beta-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-beta-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-beta-D-manno-oligosaccharides to Man is a family GH1 beta-D-mannosidase, now designated HvbetaMANNOS1, but previously identified as a beta-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) beta-D-mannoside three times faster than 4NP beta-D-glucoside, and has an action pattern typical of a (1,4)-beta-D-mannan exohydrolase.
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Hydrolysis of (1,4)-β-D-mannans in barley (Hordeum vulgare L.) is mediated by the concerted action of (1,4)-β-D-mannan endohydrolase and β-D-mannosidase
Biochemical Journal, 2006Co-Authors: Maria Hrmova, Jelle Lahnstein, Rachel A Burton, Peter Biely, Geoffrey b. FincherAbstract:A family GH5 (family 5 glycoside hydrolase) (1,4)-β-D-mannan endohydrolase or β-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pi of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K m constants of 0.16 mg · ml -1 and 5.3 mM and k cat constants of 12.9 and 3.9 s -1 respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-β-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-β-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-β-D-manno-oligosaccharides to Man is a family GH1 β-D-mannosidase, now designated HvaβMANNOS1, but previously identified as a β-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) β-D-mannoside three times faster than 4NP β-D-glucoside, and has an action pattern typical of a (1,4)-β-D-mannan exohydrolase. © 2006 Biochemical Society.
Máire Begley - One of the best experts on this subject based on the ideXlab platform.
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Bile Salt Hydrolase Activity in Probiotics Bile Salt Hydrolase Activity in Probiotics
Applied and Environmental Microbiology., 2006Co-Authors: Máire Begley, Colin Hill, Cormac G M GahanAbstract:Probiotics are defined as “living microorganisms, which upon ingestion in certain numbers exert health benefits on the host beyond inherent basic nutrition” (43). Various studies have indicated that probiotics may alleviate lactose intolerance; have a positive influence on the intestinal flora of the host; stimulate/modulate mucosal immunity; reduce inflammatory or allergic reactions; reduce blood cholesterol; possess anti-colon cancer effects; reduce the clinical manifestations of atopic dermatitis, Crohn’s disease, diarrhea, constipation, candidiasis, and urinary tract infections; and competitively exclude pathogens (35, 67, 75, 80, 99). Considering this impressive list of potential health-promoting benefits, it is not surprising that there continues to be considerable interest in the use of probiotics as biotherapeutic agents (67, 75, 82). Furthermore, given a heightened awareness among consumers of the link between diet and health and the fact that probiotic-containing foods are generally perceived as “safe” and “natural,” the global market for such foods is on the increase, particularly dairy-based products marketed for the prophylaxis or alleviation of gastrointestinal disorders (84). The selection of potential probiotic strains that would be capable of performing effectively in the gastrointestinal tract is a significant challenge. Strain selection has generally been based on in vitro tolerance of physiologically relevant stresses: e.g., low pH, elevated osmolarity, and bile (26, 53, 77, 100). In addition to these physiological assays, molecular investigations are now under way to determine the genetic basis of gastric survival and functionality (11, 78, 79) and inclusion of molecular markers identified by this approach into screening programs may lead to more well-defined and reliable results. The ability of probiotic strains to hydrolyze bile salts has often been included among the criteria for probiotic strain selection, and a number of bile salt hydrolases (BSHs) have been identified and characterized. However, microbial BSH activity has also been mooted to be potentially detrimental to the human host, and thus it is as yet not completely clear whether BSH activity is in fact a desirable trait in a probiotic bacterium. We review here the available literature on the reaction catalyzed by BSH enzymes, explore the ecological significance of BSH production, and briefly examine the impact that bile hydrolysis may have on human physiology. We conclude with suggestions for future work and possible applications of BSH research.
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Bile salt hydrolase activity in probiotics
Applied and Environmental Microbiology, 2006Co-Authors: Máire Begley, Colin Hill, Cormac G M GahanAbstract:Probiotics are defined as “living microorganisms, which upon ingestion in certain numbers exert health benefits on the host beyond inherent basic nutrition” (43). Various studies have indicated that probiotics may alleviate lactose intolerance; have a positive influence on the intestinal flora of the host; stimulate/modulate mucosal immunity; reduce inflammatory or allergic reactions; reduce blood cholesterol; possess anti-colon cancer effects; reduce the clinical manifestations of atopic dermatitis, Crohn’s disease, diarrhea, constipation, candidiasis, and urinary tract infections; and competitively exclude pathogens (35, 67, 75, 80, 99). Considering this impressive list of potential health-promoting benefits, it is not surprising that there continues to be considerable interest in the use of probiotics as biotherapeutic agents (67, 75, 82). Furthermore, given a heightened awareness among consumers of the link between diet and health and the fact that probiotic-containing foods are generally perceived as “safe” and “natural,” the global market for such foods is on the increase, particularly dairy-based products marketed for the prophylaxis or alleviation of gastrointestinal disorders (84). The selection of potential probiotic strains that would be capable of performing effectively in the gastrointestinal tract is a significant challenge. Strain selection has generally been based on in vitro tolerance of physiologically relevant stresses: e.g., low pH, elevated osmolarity, and bile (26, 53, 77, 100). In addition to these physiological assays, molecular investigations are now under way to determine the genetic basis of gastric survival and functionality (11, 78, 79) and inclusion of molecular markers identified by this approach into screening programs may lead to more well-defined and reliable results. The ability of probiotic strains to hydrolyze bile salts has often been included among the criteria for probiotic strain selection, and a number of bile salt hydrolases (BSHs) have been identified and characterized. However, microbial BSH activity has also been mooted to be potentially detrimental to the human host, and thus it is as yet not completely clear whether BSH activity is in fact a desirable trait in a probiotic bacterium. We review here the available literature on the reaction catalyzed by BSH enzymes, explore the ecological significance of BSH production, and briefly examine the impact that bile hydrolysis may have on human physiology. We conclude with suggestions for future work and possible applications of BSH research.
