The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform

Timo Lövgren - One of the best experts on this subject based on the ideXlab platform.

  • Rapid time-resolved iMMunofluorometric assay for the measurement of Creatine Kinase in serum and whole blood samples.
    Journal of agricultural and food chemistry, 2002
    Co-Authors: Mika Tuomola, Jani Vainio, Timo Lövgren
    Abstract:

    A rapid and simple iMMunochemical method was developed for the assessment of the Creatine Kinase (MM) isoenzyme [CK(MM)], a protein marker linked with animal welfare and meat quality. The one-step ...

  • Simultaneous quadruple-label fluorometric iMMunoassay of thyroid-stimulating hormone, 17 alpha-hydroxyprogesterone, iMMunoreactive trypsin, and Creatine Kinase MM isoenzyme in dried blood spots.
    Clinical chemistry, 1992
    Co-Authors: Kim Pettersson, K Blomberg, I Hemmilä, Heikki Mikola, Timo Lövgren
    Abstract:

    We describe a quadruple-label fluorometric iMMunoassay for simultaneously measuring four analytes: thyroid-stimulating hormone (TSH), 17 alpha-hydroxyprogesterone (17 alpha-OHP), iMMunoreactive trypsin (IRT), and Creatine Kinase MM (CK-MM). The assay is based on iMMunoreagents labeled with four different lanthanide ions (Eu3+, Tb3+, Sm3+, and Dy3+), on dissociative fluorescence enhancement applying the principle of co-fluorescence, and on time-resolved fluorometry. The monoclonal anti-alpha-TSH and anti-IRT antibodies and the polyclonal anti-CK-MM antibody were labeled with Eu3+, Sm3+, and Dy3+, respectively; 17 alpha-OHP was labeled with Tb3+. The assay was performed in microtitration strip wells coated with a mixture of monoclonal antibodies against beta-TSH, IRT, and CK-MM and a polyclonal goat anti-rabbit IgG for capture of the rabbit anti-17 alpha-OHP antibodies. After completion of the iMMunoreactions, the bound fractions of the lanthanides were dissociated into the co-fluorescence enhancement solution, creating highly fluorescent chelates. The four lanthanide-specific signals were subsequently measured in a time-resolved fluorometer. The detection limits of the assay were 0.1 mIU/L for TSH, 2 nmol/L for 17 alpha-OHP, 2 micrograms/L for IRT, and 4 U/L for CK-MM.

Eric Clottes - One of the best experts on this subject based on the ideXlab platform.

  • Role of C-terminal sequences in the folding of muscle Creatine Kinase.
    Biochemistry, 2002
    Co-Authors: Hortense Mazon, Olivier Marcillat, Christian Vial, Eric Clottes
    Abstract:

    Proteinase K selectively nicks the native homodimeric muscle Creatine Kinase (MM-CK) into two 37.1 kDa N-terminal (K1) and two 5.8 kDa C-terminal (K2) fragments that remain firmly associated in a nativelike, although inactive, heterotetrameric structure. This truncated protein has been named (K1K2)2. To analyze the role of the C-terminal peptide in the protein structure acquisition, we studied in vitro refolding of the guanidinium chloride-denatured (K1K2)2. Although they never reassociate with K2, in selected conditions the K1 fragments refold slowly to a dimeric state as shown by size exclusion chromatography data. This K1 dimer exhibits a fluorescence emission λmax of 335 nm, a high degree of tyrosine exposure, strongly binds ANS but not MgADP, a CK substrate, and according to these structural characteristics, could be a dimeric molten globule species. We propose a folding model that takes into account the existence of a new transient intermediate state in the MM-CK refolding process. Besides two monom...

  • Role of quaternary structure in muscle Creatine Kinase stability: Tryptophan 210 is important for dimer cohesion
    Proteins, 1998
    Co-Authors: Catherine Perraut, Eric Clottes, Christian Vial, Chantal Leydier, Olivier Marcillat
    Abstract:

    A mutant of the dimeric rabbit muscle Creatine Kinase (MM-CK) in which tryptophan 210 was replaced has been studied to assess the role of this residue in dimer cohesion and the importance of the dimeric state for the native enzyme stability. Wild-type protein equilibrium unfolding induced by guanidine hydrochloride occurs through intermediate states with formation of a molten globule and a premolten globule. Unlike the wild-type enzyme, the mutant inactivates at lower denaturant concentration and the loss of enzymatic activity is accompanied by the dissociation of the dimer into two apparently compact monomers. However, the Stokes radius of the monomer increases with denaturant concentration as determined by size exclusion chromatography, indicating that, upon monomerization, the protein structure is destabilized. Binding of 8-anilinonaphthalene-1-sulfonate shows that the dissociated monomer exposes hydrophobic patches at its surface, suggesting that it could be a molten globule. At higher denaturant concentrations, both wild-type and mutant follow similar denaturation pathways with formation of a premolten globule around 1.5-M guanidine, indicating that tryptophan 210 does not contribute to a large extent to the monomer conformational stability, which may be ensured in the dimeric state through quaternary interactions.

  • Discrimination between the Four Tryptophan Residues of MM-Creatine Kinase on the Basis of the Effect ofN-Bromosuccinimide on Activity and Spectral Properties
    Archives of biochemistry and biophysics, 1996
    Co-Authors: Eric Clottes, Christian Vial
    Abstract:

    Rabbit muscle cytosolic Creatine Kinase (MM-CK) has been treated with N-bromosuccinimide, a reagent known to oxidize selectively the indole moiety of tryptophan residues of proteins in acidic conditions. Inactivation of the enzyme is achieved by modification of one residue per monomer. NBS treatment decreases the ultraviolet absorbance at 280 nm and the intrinsic fluorescence of the protein. From these data it can be deduced that the quantum yields of the four tryptophan residues of each monomer are different due to the more or less hydrophobic environment of each of them and that at least two of them are sufficiently close to Cys 282 to allow fluorescence energy transfer to an extrinsic fluorophore bound to this residue. The accessibility to iodide of the tryptophans has been evaluated during guanidinium chloride denaturation. These data allowed us to acquire a new insight into the environment, the contribution to intrinsic fluorescence and the role in enzymatic activity and fluorescence resonance energy transfer of the tryptophan residues of CK and to tentatively assign a position in the sequence to each of them.

Christian Vial - One of the best experts on this subject based on the ideXlab platform.

  • Role of C-terminal sequences in the folding of muscle Creatine Kinase.
    Biochemistry, 2002
    Co-Authors: Hortense Mazon, Olivier Marcillat, Christian Vial, Eric Clottes
    Abstract:

    Proteinase K selectively nicks the native homodimeric muscle Creatine Kinase (MM-CK) into two 37.1 kDa N-terminal (K1) and two 5.8 kDa C-terminal (K2) fragments that remain firmly associated in a nativelike, although inactive, heterotetrameric structure. This truncated protein has been named (K1K2)2. To analyze the role of the C-terminal peptide in the protein structure acquisition, we studied in vitro refolding of the guanidinium chloride-denatured (K1K2)2. Although they never reassociate with K2, in selected conditions the K1 fragments refold slowly to a dimeric state as shown by size exclusion chromatography data. This K1 dimer exhibits a fluorescence emission λmax of 335 nm, a high degree of tyrosine exposure, strongly binds ANS but not MgADP, a CK substrate, and according to these structural characteristics, could be a dimeric molten globule species. We propose a folding model that takes into account the existence of a new transient intermediate state in the MM-CK refolding process. Besides two monom...

  • Role of quaternary structure in muscle Creatine Kinase stability: Tryptophan 210 is important for dimer cohesion
    Proteins, 1998
    Co-Authors: Catherine Perraut, Eric Clottes, Christian Vial, Chantal Leydier, Olivier Marcillat
    Abstract:

    A mutant of the dimeric rabbit muscle Creatine Kinase (MM-CK) in which tryptophan 210 was replaced has been studied to assess the role of this residue in dimer cohesion and the importance of the dimeric state for the native enzyme stability. Wild-type protein equilibrium unfolding induced by guanidine hydrochloride occurs through intermediate states with formation of a molten globule and a premolten globule. Unlike the wild-type enzyme, the mutant inactivates at lower denaturant concentration and the loss of enzymatic activity is accompanied by the dissociation of the dimer into two apparently compact monomers. However, the Stokes radius of the monomer increases with denaturant concentration as determined by size exclusion chromatography, indicating that, upon monomerization, the protein structure is destabilized. Binding of 8-anilinonaphthalene-1-sulfonate shows that the dissociated monomer exposes hydrophobic patches at its surface, suggesting that it could be a molten globule. At higher denaturant concentrations, both wild-type and mutant follow similar denaturation pathways with formation of a premolten globule around 1.5-M guanidine, indicating that tryptophan 210 does not contribute to a large extent to the monomer conformational stability, which may be ensured in the dimeric state through quaternary interactions.

  • Discrimination between the Four Tryptophan Residues of MM-Creatine Kinase on the Basis of the Effect ofN-Bromosuccinimide on Activity and Spectral Properties
    Archives of biochemistry and biophysics, 1996
    Co-Authors: Eric Clottes, Christian Vial
    Abstract:

    Rabbit muscle cytosolic Creatine Kinase (MM-CK) has been treated with N-bromosuccinimide, a reagent known to oxidize selectively the indole moiety of tryptophan residues of proteins in acidic conditions. Inactivation of the enzyme is achieved by modification of one residue per monomer. NBS treatment decreases the ultraviolet absorbance at 280 nm and the intrinsic fluorescence of the protein. From these data it can be deduced that the quantum yields of the four tryptophan residues of each monomer are different due to the more or less hydrophobic environment of each of them and that at least two of them are sufficiently close to Cys 282 to allow fluorescence energy transfer to an extrinsic fluorophore bound to this residue. The accessibility to iodide of the tryptophans has been evaluated during guanidinium chloride denaturation. These data allowed us to acquire a new insight into the environment, the contribution to intrinsic fluorescence and the role in enzymatic activity and fluorescence resonance energy transfer of the tryptophan residues of CK and to tentatively assign a position in the sequence to each of them.

Ana Luisa Miranda-vilela - One of the best experts on this subject based on the ideXlab platform.

  • Creatine Kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels
    European Journal of Applied Physiology, 2012
    Co-Authors: Ana Luisa Miranda-vilela, Arthur K. Akimoto, Graciana Souza Lordelo, Luiz C. S. Pereira, Cesar Koppe Grisolia, Maria De Nazaré Klautau-guimarães
    Abstract:

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflaMMatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type Creatine Kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM Taq I and Nco I, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflaMMation markers. Blood samples were taken iMMediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM Taq I polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. The results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflaMMation or protection against it, and perhaps affect future risks of CVD in athletes.

  • Creatine Kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels
    European Journal of Applied Physiology, 2012
    Co-Authors: Ana Luisa Miranda-vilela, Arthur K. Akimoto, Graciana Souza Lordelo, Luiz C. S. Pereira, Cesar Koppe Grisolia, Maria De Nazaré Klautau-guimarães
    Abstract:

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflaMMatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type Creatine Kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM Taq I and Nco I, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflaMMation markers. Blood samples were taken iMMediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM Taq I polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. Results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflaMMation or protection against it, and perhaps affect future risks of CVD in athletes.

  • Creatine Kinase MM Taq
    European journal of applied physiology, 2011
    Co-Authors: Ana Luisa Miranda-vilela, Arthur K. Akimoto, Graciana Souza Lordelo, Luiz C. S. Pereira, Cesar Koppe Grisolia, Maria De Nazaré Klautau-guimarães
    Abstract:

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflaMMatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type Creatine Kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM TaqI and NcoI, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflaMMation markers. Blood samples were taken iMMediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM TaqI polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. The results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflaMMation or protection against it, and perhaps affect future risks of CVD in athletes.

Maria De Nazaré Klautau-guimarães - One of the best experts on this subject based on the ideXlab platform.

  • Creatine Kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels
    European Journal of Applied Physiology, 2012
    Co-Authors: Ana Luisa Miranda-vilela, Arthur K. Akimoto, Graciana Souza Lordelo, Luiz C. S. Pereira, Cesar Koppe Grisolia, Maria De Nazaré Klautau-guimarães
    Abstract:

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflaMMatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type Creatine Kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM Taq I and Nco I, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflaMMation markers. Blood samples were taken iMMediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM Taq I polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. The results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflaMMation or protection against it, and perhaps affect future risks of CVD in athletes.

  • Creatine Kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels
    European Journal of Applied Physiology, 2012
    Co-Authors: Ana Luisa Miranda-vilela, Arthur K. Akimoto, Graciana Souza Lordelo, Luiz C. S. Pereira, Cesar Koppe Grisolia, Maria De Nazaré Klautau-guimarães
    Abstract:

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflaMMatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type Creatine Kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM Taq I and Nco I, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflaMMation markers. Blood samples were taken iMMediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM Taq I polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. Results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflaMMation or protection against it, and perhaps affect future risks of CVD in athletes.