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Christiane Jung - One of the best experts on this subject based on the ideXlab platform.
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Structural changes in cytochrome P-450cam effected by the binding of the enantiomers (1R)-Camphor and (1S)-Camphor.
Biochemistry, 1996Co-Authors: Heike Schulze, Gaston Hui Bon Hoa, Volkhard Helms, Rebecca C. Wade, Christiane JungAbstract:A comparative study of the enantiomeric substrate [(1R)-Camphor- and (1S)-Camphor)-bound cytochrome P-450cam concerns the spin-state equilibrium, substrate dissociation, the thermal unfolding of the protein structure, and the subconformer equilibria observed in the infrared spectra of the carbon monoxide (CO) complex of cytochrome P-450cam. The behavior of the different conformational equilibria in dependence on temperature, pressure, pH-value, cosolvent, and cation binding led us to suggest that (1S)-Camphor is more loosely and less optimally bound in the heme pocket, which facilitates the access of solvent molecules into the heme-iron environment. The spin reaction volume difference measured using the high pressure technique is smaller by 16 ± 9 cm3/mol for (1S)-Camphor-bound P-450cam compared to the (1R)-Camphor-bound P-450cam, which might indicate a higher water content in the protein and in the heme environment in the (1S)-Camphor complex. The half-transition temperature of the thermal unfolding of 5...
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Time-resolved Fourier-transform infrared studies of the cytochrome P-450cam carbonmonoxide complex bound with (1R)-Camphor and (1S)-Camphor substrate.
FEBS Letters, 1996Co-Authors: Jörg Contzen, O. Ristau, Christiane JungAbstract:The CO-binding reaction of cytochrome P-450cam bound with (1R)-Camphor and (1S)-Camphor are compared in the temperature region of 210–260 K using time-resolved Fourier-transform infrared spectroscopy with the CO stretch vibration as spectroscopic probe. For (1S)-Camphor as substrate the association of CO is slowed down by a factor of 2, while the dissociation is accelerated by a factor of 3. The CO complex for the (1S)-Camphor-bound P-450 is less stabilized (ΔG=−22 kJ/mol) compared to the natural substrate (1R)-Camphor (ΔG=−30 kJ/mol). The data are interpreted by a smaller change of the mobility of the (1S)-Camphor due to CO binding as compared to (1R)-Camphor, which would indicate a higher mobility of (1S)-Camphor already in the CO free reduced form of P-450cam. The higher mobility of (1S)-Camphor in the heme pocket might explain the increased uncoupling rate (hydrogen peroxide formation) of 11% [Maryniak et al. (1993) Tetrahedron 49, 9373–9384] during the P-450cam catalyzed hydroxylation compared to 3% for the conversion of (1R)-Camphor.
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Time-resolved Fourier-transform infrared studies of the cytochrome P-450cam carbonmonoxide complex bound with (1R)-Camphor and (1S)-Camphor substrate.
FEBS letters, 1996Co-Authors: Jörg Contzen, O. Ristau, Christiane JungAbstract:The CO-binding reaction of cytochrome P-450cam bound with (1R)-Camphor and (1S)-Camphor are compared in the temperature region of 210-260 K using time-resolved Fourier-transform infrared spectroscopy with the CO stretch vibration as spectroscopic probe. For (1S)-Camphor as substrate the association of CO is slowed down by a factor of 2, while the dissociation is accelerated by a factor of 3. The CO complex for the (1S)-Camphor-bound P-450 is less stabilized (deltaG=-22 kJ/mol) compared to the natural substrate (1R)-Camphor (deltaG=-30 kJ/mol). The data are interpreted by a smaller change of the mobility of the (1S)-Camphor due to CO binding as compared to (1R)-Camphor, which would indicate a higher mobility of (1S)-Camphor already in the CO free reduced form of P-450cam. The higher mobility of (1S)-Camphor in the heme pocket might explain the increased uncoupling rate (hydrogen peroxide formation) of 11% [Maryniak et al. (1993) Tetrahedron 49, 9373-9384] during the P-450cam catalyzed hydroxylation compared to 3% for the conversion of (1R)-Camphor.
David E Clapham - One of the best experts on this subject based on the ideXlab platform.
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Camphor activates and strongly desensitizes the transient receptor potential vanilloid subtype 1 channel in a vanilloid independent mechanism
The Journal of Neuroscience, 2005Co-Authors: Nathaniel T Blair, David E ClaphamAbstract:Camphor is a naturally occurring compound that is used as a major active ingredient of balms and liniments supplied as topical analgesics. Despite its long history of common medical use, the underlying molecular mechanism of Camphor action is not understood. Capsaicin and menthol, two other topically applied agents widely used for similar purposes, are known to excite and desensitize sensory nerves by acting on two members of transient receptor potential (TRP) channel superfamily: heat-sensitive TRP vanilloid subtype 1 (TRPV1) and cold-sensitive TRP channel M8, respectively. Camphor has recently been shown to activate TRPV3, and here we show that Camphor also activates heterologously expressed TRPV1, requiring higher concentrations than capsaicin. Activation was enhanced by phospholipase C-coupled receptor stimulation mimicking inflamed conditions. Similar Camphor-activated TRPV1-like currents were observed in isolated rat DRG neurons and were strongly potentiated after activation of protein kinase C with phorbol-12-myristate-13-acetate. Camphor activation of rat TRPV1 was mediated by distinct channel regions from capsaicin, as indicated by Camphor activation in the presence of the competitive inhibitor capsazepine and in a capsaicin-insensitive point mutant. Camphor did not activate the capsaicin-insensitive chicken TRPV1. TRPV1 desensitization is believed to contribute to the analgesic actions of capsaicin. We found that, although Camphor activates TRPV1 less effectively, Camphor application desensitized TRPV1 more rapidly and completely than capsaicin. Conversely, TRPV3 current sensitized after repeated Camphor applications, which is inconsistent with the analgesic role of Camphor. We also found that Camphor inhibited several other related TRP channels, including ankyrin-repeat TRP 1 (TRPA1). The Camphor-induced desensitization of TRPV1 and block of TRPA1 may underlie the analgesic effects of Camphor.
Jörg Contzen - One of the best experts on this subject based on the ideXlab platform.
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Time-resolved Fourier-transform infrared studies of the cytochrome P-450cam carbonmonoxide complex bound with (1R)-Camphor and (1S)-Camphor substrate.
FEBS Letters, 1996Co-Authors: Jörg Contzen, O. Ristau, Christiane JungAbstract:The CO-binding reaction of cytochrome P-450cam bound with (1R)-Camphor and (1S)-Camphor are compared in the temperature region of 210–260 K using time-resolved Fourier-transform infrared spectroscopy with the CO stretch vibration as spectroscopic probe. For (1S)-Camphor as substrate the association of CO is slowed down by a factor of 2, while the dissociation is accelerated by a factor of 3. The CO complex for the (1S)-Camphor-bound P-450 is less stabilized (ΔG=−22 kJ/mol) compared to the natural substrate (1R)-Camphor (ΔG=−30 kJ/mol). The data are interpreted by a smaller change of the mobility of the (1S)-Camphor due to CO binding as compared to (1R)-Camphor, which would indicate a higher mobility of (1S)-Camphor already in the CO free reduced form of P-450cam. The higher mobility of (1S)-Camphor in the heme pocket might explain the increased uncoupling rate (hydrogen peroxide formation) of 11% [Maryniak et al. (1993) Tetrahedron 49, 9373–9384] during the P-450cam catalyzed hydroxylation compared to 3% for the conversion of (1R)-Camphor.
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Time-resolved Fourier-transform infrared studies of the cytochrome P-450cam carbonmonoxide complex bound with (1R)-Camphor and (1S)-Camphor substrate.
FEBS letters, 1996Co-Authors: Jörg Contzen, O. Ristau, Christiane JungAbstract:The CO-binding reaction of cytochrome P-450cam bound with (1R)-Camphor and (1S)-Camphor are compared in the temperature region of 210-260 K using time-resolved Fourier-transform infrared spectroscopy with the CO stretch vibration as spectroscopic probe. For (1S)-Camphor as substrate the association of CO is slowed down by a factor of 2, while the dissociation is accelerated by a factor of 3. The CO complex for the (1S)-Camphor-bound P-450 is less stabilized (deltaG=-22 kJ/mol) compared to the natural substrate (1R)-Camphor (deltaG=-30 kJ/mol). The data are interpreted by a smaller change of the mobility of the (1S)-Camphor due to CO binding as compared to (1R)-Camphor, which would indicate a higher mobility of (1S)-Camphor already in the CO free reduced form of P-450cam. The higher mobility of (1S)-Camphor in the heme pocket might explain the increased uncoupling rate (hydrogen peroxide formation) of 11% [Maryniak et al. (1993) Tetrahedron 49, 9373-9384] during the P-450cam catalyzed hydroxylation compared to 3% for the conversion of (1R)-Camphor.
Murray B Isman - One of the best experts on this subject based on the ideXlab platform.
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Enhanced cuticular penetration as the mechanism for synergy of insecticidal constituents of rosemary essential oil in Trichoplusia ni
Scientific Reports, 2015Co-Authors: Jun-hyung Tak, Murray B IsmanAbstract:Synergistic interactions between constituents of essential oils have been reported for several areas of research. In the present study, mechanisms that could explain the synergistic action of the two major insecticidal constituents of rosemary oil, 1,8-cineole and Camphor against the cabbage looper, Trichoplusia ni were investigated. 1,8-Cineole was more toxic than Camphor when applied topically to larvae and when coadministered in their ratio naturally occurring in rosemary oil, the binary mixture was synergistic. However, when injected directly into larvae, Camphor was more toxic than 1,8-cineole. GC-MS analyses showed that penetration of topically-applied Camphor was significantly enhanced when it was mixed with 1,8-cineole in the natural ratio. A bioassay combining injection and topical application methods confirmed the increased penetration of both compounds when mixed, showing the same bioactivity as seen for higher amounts applied individually. Lowered surface tension as well as increased solubility of Camphor by 1,8-cineole, along with the interaction between 1,8-cineole and the lipid layer of the insect’s cuticle may explain the enhanced penetration of Camphor. Because of the similarities in biological function of animal and microbial membranes, our finding has potential for application in other fields of study.
Nathaniel T Blair - One of the best experts on this subject based on the ideXlab platform.
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Camphor activates and strongly desensitizes the transient receptor potential vanilloid subtype 1 channel in a vanilloid independent mechanism
The Journal of Neuroscience, 2005Co-Authors: Nathaniel T Blair, David E ClaphamAbstract:Camphor is a naturally occurring compound that is used as a major active ingredient of balms and liniments supplied as topical analgesics. Despite its long history of common medical use, the underlying molecular mechanism of Camphor action is not understood. Capsaicin and menthol, two other topically applied agents widely used for similar purposes, are known to excite and desensitize sensory nerves by acting on two members of transient receptor potential (TRP) channel superfamily: heat-sensitive TRP vanilloid subtype 1 (TRPV1) and cold-sensitive TRP channel M8, respectively. Camphor has recently been shown to activate TRPV3, and here we show that Camphor also activates heterologously expressed TRPV1, requiring higher concentrations than capsaicin. Activation was enhanced by phospholipase C-coupled receptor stimulation mimicking inflamed conditions. Similar Camphor-activated TRPV1-like currents were observed in isolated rat DRG neurons and were strongly potentiated after activation of protein kinase C with phorbol-12-myristate-13-acetate. Camphor activation of rat TRPV1 was mediated by distinct channel regions from capsaicin, as indicated by Camphor activation in the presence of the competitive inhibitor capsazepine and in a capsaicin-insensitive point mutant. Camphor did not activate the capsaicin-insensitive chicken TRPV1. TRPV1 desensitization is believed to contribute to the analgesic actions of capsaicin. We found that, although Camphor activates TRPV1 less effectively, Camphor application desensitized TRPV1 more rapidly and completely than capsaicin. Conversely, TRPV3 current sensitized after repeated Camphor applications, which is inconsistent with the analgesic role of Camphor. We also found that Camphor inhibited several other related TRP channels, including ankyrin-repeat TRP 1 (TRPA1). The Camphor-induced desensitization of TRPV1 and block of TRPA1 may underlie the analgesic effects of Camphor.