The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Brian W. Metcalf - One of the best experts on this subject based on the ideXlab platform.
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Epristeride is a selective and specific Uncompetitive Inhibitor of human steroid 5α-reductase isoform 2
The Journal of Steroid Biochemistry and Molecular Biology, 1994Co-Authors: Mark Alan Levy, Martin Brandt, Kristina M. Sheedy, Jeffrey T. Dinh, Dennis A. Holt, Linda M. Garrison, Derk J. Bergsma, Brian W. MetcalfAbstract:Specificity of an enzyme Inhibitor can have profound implications upon the compound's therapeutic potential, utility and safety profile. As potent Inhibitors of human steroid 5 alpha-reductase (SR) the 3-androstene-3-carboxylic acids, or steroidal acrylates, may be useful in treatment of diseases such as benign prostatic hyperplasia for which 5 alpha-dihydrotestosterone (DHT) appears to be a causative agent. To determine its specificity profile, the interactions of a representative compound from this class, N-(t-butyl)androst-3,5-diene-17 beta-carboxamide-3-carboxylic acid (epristeride, SK&F 105657), have been studied with 7 other steroid processing enzymes and 5 steroid hormone receptors. The affinity of epristeride for each of these 12 potential targets was found to be at least 1000-fold weaker than that for SR, the intended target. In addition, using samples of the individually expressed two known forms of human SRs, epristeride has been shown to be a selective Inhibitor of the recombinant human SR type 2, the predominant activity found in the prostate of man. Nonetheless, the mechanisms of SR inhibition for both isoenzymes involve formation of a ternary complex with epristeride, NADP+, and enzyme. Epristeride, consequently, has been shown to be an Uncompetitive Inhibitor versus steroid substrate of both human SR isoenzymes. These results suggest that this 3-androstene-3-carboxylic acid is a specific and selective Inhibitor of the human type 2 SR, and that epristeride is an attractive compound for further investigation as a safe and effective therapeutic agent in the potential treatment of disease states associated with DHT-induced tissue growth.
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Epristeride is a selective and specific Uncompetitive Inhibitor of human steroid 5 alpha-reductase isoform 2.
The Journal of steroid biochemistry and molecular biology, 1994Co-Authors: Mark Alan Levy, Martin Brandt, Kristina M. Sheedy, Jeffrey T. Dinh, Dennis A. Holt, Linda M. Garrison, Derk J. Bergsma, Brian W. MetcalfAbstract:Specificity of an enzyme Inhibitor can have profound implications upon the compound's therapeutic potential, utility and safety profile. As potent Inhibitors of human steroid 5 alpha-reductase (SR) the 3-androstene-3-carboxylic acids, or steroidal acrylates, may be useful in treatment of diseases such as benign prostatic hyperplasia for which 5 alpha-dihydrotestosterone (DHT) appears to be a causative agent. To determine its specificity profile, the interactions of a representative compound from this class, N-(t-butyl)androst-3,5-diene-17 beta-carboxamide-3-carboxylic acid (epristeride, SK&F 105657), have been studied with 7 other steroid processing enzymes and 5 steroid hormone receptors. The affinity of epristeride for each of these 12 potential targets was found to be at least 1000-fold weaker than that for SR, the intended target. In addition, using samples of the individually expressed two known forms of human SRs, epristeride has been shown to be a selective Inhibitor of the recombinant human SR type 2, the predominant activity found in the prostate of man. Nonetheless, the mechanisms of SR inhibition for both isoenzymes involve formation of a ternary complex with epristeride, NADP+, and enzyme. Epristeride, consequently, has been shown to be an Uncompetitive Inhibitor versus steroid substrate of both human SR isoenzymes. These results suggest that this 3-androstene-3-carboxylic acid is a specific and selective Inhibitor of the human type 2 SR, and that epristeride is an attractive compound for further investigation as a safe and effective therapeutic agent in the potential treatment of disease states associated with DHT-induced tissue growth.
Juliet A Gerrard - One of the best experts on this subject based on the ideXlab platform.
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dihydrodipicolinate synthase dhdps from escherichia coli displays partial mixed inhibition with respect to its first substrate pyruvate
Biochimie, 2004Co-Authors: Renwick C J Dobson, Michael D W Griffin, Sarah Roberts, Juliet A GerrardAbstract:Abstract Dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52) mediates the first unique reaction of ( S )-lysine biosynthesis in plants and microbes—the condensation of ( S )-aspartate-β-semialdehyde (( S )-ASA) and pyruvate. It has been shown that DHDPS is partially feedback inhibited by ( S )-lysine; it is suggested that this mechanism regulates flux through the DAP biosynthetic pathway. Others have characterised DHDPS from Escherichia coli with respect to ( S )-lysine inhibition. They have concluded that, with respect to pyruvate, the first substrate of the reaction, DHDPS shows Uncompetitive inhibition: as such, they further suggest that ( S )-lysine inhibits DHDPS via interaction with the binding site for the second substrate, ( S )-ASA. Yet, this finding is based on the assumption that ( S )-lysine is a fully Uncompetitive Inhibitor. In light of crystallographic studies, which lead to the proposal that ( S )-lysine affects the putative proton-relay of DHDPS, we re-evaluated the inhibition mechanism of DHDPS with respect to ( S )-lysine by incorporating the observed hyperbolic inhibition. Our data showed that lysine is not an Uncompetitive Inhibitor, but a mixed Inhibitor when pyruvate and ( S )-lysine concentrations were varied. Thus, consistent with the crystallographic data, ( S )-lysine must have an effect on the initial steps of the DHDPS reaction, including the binding of pyruvate and Schiff base formation.
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Dihydrodipicolinate synthase (DHDPS) from Escherichia coli displays partial mixed inhibition with respect to its first substrate, pyruvate.
Biochimie, 2004Co-Authors: Renwick C J Dobson, Michael D W Griffin, Sarah J Roberts, Juliet A GerrardAbstract:Dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52) mediates the first unique reaction of (S)-lysine biosynthesis in plants and microbes-the condensation of (S)-aspartate-beta-semialdehyde ((S)-ASA) and pyruvate. It has been shown that DHDPS is partially feedback inhibited by (S)-lysine; it is suggested that this mechanism regulates flux through the DAP biosynthetic pathway. Others have characterised DHDPS from Escherichia coli with respect to (S)-lysine inhibition. They have concluded that, with respect to pyruvate, the first substrate of the reaction, DHDPS shows Uncompetitive inhibition: as such, they further suggest that (S)-lysine inhibits DHDPS via interaction with the binding site for the second substrate, (S)-ASA. Yet, this finding is based on the assumption that (S)-lysine is a fully Uncompetitive Inhibitor. In light of crystallographic studies, which lead to the proposal that (S)-lysine affects the putative proton-relay of DHDPS, we re-evaluated the inhibition mechanism of DHDPS with respect to (S)-lysine by incorporating the observed hyperbolic inhibition. Our data showed that lysine is not an Uncompetitive Inhibitor, but a mixed Inhibitor when pyruvate and (S)-lysine concentrations were varied. Thus, consistent with the crystallographic data, (S)-lysine must have an effect on the initial steps of the DHDPS reaction, including the binding of pyruvate and Schiff base formation.
Mark Alan Levy - One of the best experts on this subject based on the ideXlab platform.
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Epristeride is a selective and specific Uncompetitive Inhibitor of human steroid 5α-reductase isoform 2
The Journal of Steroid Biochemistry and Molecular Biology, 1994Co-Authors: Mark Alan Levy, Martin Brandt, Kristina M. Sheedy, Jeffrey T. Dinh, Dennis A. Holt, Linda M. Garrison, Derk J. Bergsma, Brian W. MetcalfAbstract:Specificity of an enzyme Inhibitor can have profound implications upon the compound's therapeutic potential, utility and safety profile. As potent Inhibitors of human steroid 5 alpha-reductase (SR) the 3-androstene-3-carboxylic acids, or steroidal acrylates, may be useful in treatment of diseases such as benign prostatic hyperplasia for which 5 alpha-dihydrotestosterone (DHT) appears to be a causative agent. To determine its specificity profile, the interactions of a representative compound from this class, N-(t-butyl)androst-3,5-diene-17 beta-carboxamide-3-carboxylic acid (epristeride, SK&F 105657), have been studied with 7 other steroid processing enzymes and 5 steroid hormone receptors. The affinity of epristeride for each of these 12 potential targets was found to be at least 1000-fold weaker than that for SR, the intended target. In addition, using samples of the individually expressed two known forms of human SRs, epristeride has been shown to be a selective Inhibitor of the recombinant human SR type 2, the predominant activity found in the prostate of man. Nonetheless, the mechanisms of SR inhibition for both isoenzymes involve formation of a ternary complex with epristeride, NADP+, and enzyme. Epristeride, consequently, has been shown to be an Uncompetitive Inhibitor versus steroid substrate of both human SR isoenzymes. These results suggest that this 3-androstene-3-carboxylic acid is a specific and selective Inhibitor of the human type 2 SR, and that epristeride is an attractive compound for further investigation as a safe and effective therapeutic agent in the potential treatment of disease states associated with DHT-induced tissue growth.
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Epristeride is a selective and specific Uncompetitive Inhibitor of human steroid 5 alpha-reductase isoform 2.
The Journal of steroid biochemistry and molecular biology, 1994Co-Authors: Mark Alan Levy, Martin Brandt, Kristina M. Sheedy, Jeffrey T. Dinh, Dennis A. Holt, Linda M. Garrison, Derk J. Bergsma, Brian W. MetcalfAbstract:Specificity of an enzyme Inhibitor can have profound implications upon the compound's therapeutic potential, utility and safety profile. As potent Inhibitors of human steroid 5 alpha-reductase (SR) the 3-androstene-3-carboxylic acids, or steroidal acrylates, may be useful in treatment of diseases such as benign prostatic hyperplasia for which 5 alpha-dihydrotestosterone (DHT) appears to be a causative agent. To determine its specificity profile, the interactions of a representative compound from this class, N-(t-butyl)androst-3,5-diene-17 beta-carboxamide-3-carboxylic acid (epristeride, SK&F 105657), have been studied with 7 other steroid processing enzymes and 5 steroid hormone receptors. The affinity of epristeride for each of these 12 potential targets was found to be at least 1000-fold weaker than that for SR, the intended target. In addition, using samples of the individually expressed two known forms of human SRs, epristeride has been shown to be a selective Inhibitor of the recombinant human SR type 2, the predominant activity found in the prostate of man. Nonetheless, the mechanisms of SR inhibition for both isoenzymes involve formation of a ternary complex with epristeride, NADP+, and enzyme. Epristeride, consequently, has been shown to be an Uncompetitive Inhibitor versus steroid substrate of both human SR isoenzymes. These results suggest that this 3-androstene-3-carboxylic acid is a specific and selective Inhibitor of the human type 2 SR, and that epristeride is an attractive compound for further investigation as a safe and effective therapeutic agent in the potential treatment of disease states associated with DHT-induced tissue growth.
Deepti Saini - One of the best experts on this subject based on the ideXlab platform.
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a phage antibody to the active site of human placental alkaline phosphatase with higher affinity to the enzyme substrate complex
Molecular Immunology, 2007Co-Authors: Vishal Jain, Deepti Saini, Pooja Goswami, Subrata SinhaAbstract:Selection of specific antibodies from large repertoires is of importance in generating antibodies to specific structural determinants and in studying structure-function relationships. Alkaline phosphatase (AP) has several isozymes with various degrees of homology and a range of common synthetic substrates. We have previously reported the generation of isozyme specific anti-enzyme antibodies to an oncofetal antigen, placental alkaline phosphatase (PLAP) by using a specific Uncompetitive Inhibitor, L-Phe-Gly-Gly along with the substrate para-nitrophenyl phosphate (pNPP), to elute scFvs from a phage-displayed immunoglobulin library. These antibodies were directed to the active site and inhibited enzyme activity. An Uncompetitive Inhibitor acts by stabilizing the enzyme-substrate (ES) complex. In the present work, we report the characteristics of a clone VE5, selected by the same method. This clone has a higher binding affinity for ES complex than for enzyme alone. This is true for all the three isozymes (placental, bone and intestinal) tested. However, the other synthetic small molecular substrate, disodium phenyl phosphate inhibits phage binding. The clone possibly binds to the conserved structures of the active site of the AP isozymes and the higher affinity binding to AP-pNPP complex reflects the method of selection. Such anti-enzyme antibodies have a possible potential role in dissecting structure-function relationship of enzymatic antigens.
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targeting the active site of the placental isozyme of alkaline phosphatase by phage displayed scfv antibodies selected by a specific Uncompetitive Inhibitor
BMC Biotechnology, 2005Co-Authors: Deepti Saini, Mrinalini Kala, Vishal Jain, Subrata SinhaAbstract:Background The isozymes of alkaline phosphatase, the tissue non-specific, intestinal and placental, have similar properties and a high degree of identity. The placental isozyme (PLAP) is an oncofetal antigen expressed in several malignancies including choriocarcinoma, seminoma and ovarian carcinoma. We had earlier attempted to isolate PLAP-specific scFv from a synthetic human immunoglobulin library but were unable to do so, presumably because of the similarity between the isozymes. In this work, we have employed a PLAP-specific Uncompetitive Inhibitor, L-Phe-Gly-Gly, to select isozyme specific scFvs. An Uncompetitive Inhibitor binds to the enzyme in the presence of substrate and stabilizes the enzyme-substrate complex. Several Uncompetitive Inhibitors have varying degrees of isozyme specificity for human alkaline phosphatase isozymes. A specific Uncompetitive Inhibitor would be able to unmask conformational differences between the otherwise very similar molecules. Also, such Inhibitors would be directed to regions at/close to the active site of the enzyme. In this work, the library was first incubated with PLAP and the bound clones then eluted by incubation with L-Phe-Gly-Gly along with the substrate, para-nitro phenyl phosphate (pNPP). The scFvs were then studied with regard to the biochemical modulation of their binding, isozyme specificity and effect on enzyme activity.
Subrata Sinha - One of the best experts on this subject based on the ideXlab platform.
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a phage antibody to the active site of human placental alkaline phosphatase with higher affinity to the enzyme substrate complex
Molecular Immunology, 2007Co-Authors: Vishal Jain, Deepti Saini, Pooja Goswami, Subrata SinhaAbstract:Selection of specific antibodies from large repertoires is of importance in generating antibodies to specific structural determinants and in studying structure-function relationships. Alkaline phosphatase (AP) has several isozymes with various degrees of homology and a range of common synthetic substrates. We have previously reported the generation of isozyme specific anti-enzyme antibodies to an oncofetal antigen, placental alkaline phosphatase (PLAP) by using a specific Uncompetitive Inhibitor, L-Phe-Gly-Gly along with the substrate para-nitrophenyl phosphate (pNPP), to elute scFvs from a phage-displayed immunoglobulin library. These antibodies were directed to the active site and inhibited enzyme activity. An Uncompetitive Inhibitor acts by stabilizing the enzyme-substrate (ES) complex. In the present work, we report the characteristics of a clone VE5, selected by the same method. This clone has a higher binding affinity for ES complex than for enzyme alone. This is true for all the three isozymes (placental, bone and intestinal) tested. However, the other synthetic small molecular substrate, disodium phenyl phosphate inhibits phage binding. The clone possibly binds to the conserved structures of the active site of the AP isozymes and the higher affinity binding to AP-pNPP complex reflects the method of selection. Such anti-enzyme antibodies have a possible potential role in dissecting structure-function relationship of enzymatic antigens.
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targeting the active site of the placental isozyme of alkaline phosphatase by phage displayed scfv antibodies selected by a specific Uncompetitive Inhibitor
BMC Biotechnology, 2005Co-Authors: Deepti Saini, Mrinalini Kala, Vishal Jain, Subrata SinhaAbstract:Background The isozymes of alkaline phosphatase, the tissue non-specific, intestinal and placental, have similar properties and a high degree of identity. The placental isozyme (PLAP) is an oncofetal antigen expressed in several malignancies including choriocarcinoma, seminoma and ovarian carcinoma. We had earlier attempted to isolate PLAP-specific scFv from a synthetic human immunoglobulin library but were unable to do so, presumably because of the similarity between the isozymes. In this work, we have employed a PLAP-specific Uncompetitive Inhibitor, L-Phe-Gly-Gly, to select isozyme specific scFvs. An Uncompetitive Inhibitor binds to the enzyme in the presence of substrate and stabilizes the enzyme-substrate complex. Several Uncompetitive Inhibitors have varying degrees of isozyme specificity for human alkaline phosphatase isozymes. A specific Uncompetitive Inhibitor would be able to unmask conformational differences between the otherwise very similar molecules. Also, such Inhibitors would be directed to regions at/close to the active site of the enzyme. In this work, the library was first incubated with PLAP and the bound clones then eluted by incubation with L-Phe-Gly-Gly along with the substrate, para-nitro phenyl phosphate (pNPP). The scFvs were then studied with regard to the biochemical modulation of their binding, isozyme specificity and effect on enzyme activity.
