Compact, transportable, and multipurpose high-pressure unit for UV–VIS spectroscopic measurements at pressures up to 200 MPa

Spitzer, Markus; Gartig, F.; Eldik, Rudi van

doi:10.1063/1.1140034

Cited by 89 publications

(67 citation statements)

References 1 publication

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“…Cu(CF 3 Equipment: Absorption UV/Vis spectra were recorded on 2101PC (Shimadzu, Kyoto, Japan) and Cary 5G (Varian, Palo Alto, CA, USA) spectrophotometers equipped with electronic temperature controllers. A custom-built high-pressure probe [64] combined with the Shimadzu 2101PC spectrometer was used in the high-pressure experiments. Fluorescence spectra were recorded using a LS55 spectrofluorimeter (Perkin-Elmer, Wellesley, MA, USA) equipped with a LTD6G thermostat (Grant Instruments Ltd., Cambridge, UK).…”

Section: Solvents and Reagentsmentioning

confidence: 99%

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

et al. 2009

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Chlorophyll a and pheophytin a have been treated with various metal salts in solution. As a result, metallo derivatives of photosynthetic pigments were formed, or the chlorine ring was oxidized. These studies showed that both effects can be caused by Cu II ions depending on the redox potential of its complexes formed in specific media. In this report the results of studies on metal insertion and exchange reactions are presented. According to the common use of the "acetate method" in the synthesis of metallotetrapyrroles, and the fact that acetates coordinated to Cu II ions protect chlorophylls from oxidative degradation, Cu II acetate monohydrate was selected as main reagent. The metalation and transmetalation processes were investigated with spectroscopic (UV/ Vis absorption and emission) and kinetic (conventional and high-pressure) techniques. It turned out that differences in solvent properties can significantly affect not only the rates (metalation), but also the course (transmetalation) of the reaction. The most pronounced effect was found for the trans-

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Section: Solvents and Reagentsmentioning

confidence: 99%

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

et al. 2009

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“…The sample can be illuminated, watched, moved in three dimensions, and highly sensitive electrical equipment for patch-clamp recording is provided in the autoclave. Another high-pressure marvel is the 'portable spectroscopy unit' reported by Spitzer et al (1988).…”

Section: Experimental Facilities and Methodsmentioning

confidence: 99%

Proteins under pressure

Groß

Jaenicke

1994

European Journal of Biochemistry

661

393

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Oceans not only cover the major part of the earth's surface but also reach into depths exceeding the height of the Mt Everest. They are populated down to the deepest levels (=11800 m), which means that a significant proportion of the global biosphere is exposed to pressures of up to 120 MPa. Although this fact has been known for more than a century, the ecology of the 'abyss' is still in its infancy. Only recently, barophilic adaptation, i.e. the requirement of elevated pressure for viability, has been firmly established. In non-adapted organisms, increased pressure leads to morphological anomalies or growth inhibition, and ultimately to cell death. The detailed molecular mechanism of the underlying 'metabolic dislocation' is unresolved.Effects of pressure as a variable in microbiology, biochemistry and biotechnology allow the structure/function relationship of proteins and protein conjugates to be analyzed. In this context, stabilization by cofactors or accessory proteins has been observed. High-pressure equipment available today allows the comprehensive characterization of the behaviour of proteins under pressure. Single-chain proteins undergo pressure-induced denaturation in the 100-MPa range, which, in the case of oligomeric proteins or protein assemblies, is preceded by dissociation at lower pressure. The effects may be ascribed to the positive reaction volumes connected with the formation of hydrophobic and ionic interactions. In addition, the possibility of conformational effects exerted by moderate, non-denaturing pressures, and related to the intrinsic compressibility of proteins, is discussed. Crystallization may serve as a model reaction of protein self-organization. Kinetic aspects of its pressureinduced inhibition can be described by a model based on the Oosawa theory of molecular association. Barosensitivity is known to be correlated with the pressure-induced inhibition of protein biosynthesis. Attempts to track down the ultimate cause in the dissociation of ribosomes have revealed remarkable stabilization of functional complexes under pseudo-physiological conditions, with the post-translational complex as the most pressure-sensitive species. Apart from the key issue of barosensitivity and barophilic adaptation, high-pressure biochemistry may provide means to develop new approaches to nonthermic industrial processes, especially in the field of food technology.Life in the deep sea faces a whole set of unfavourable conditions, including pressures up to 120 MPa (1200 bar), temperatures around 2°C or, in volcanic regions, above 1OO"C, absence of sunlight, and scarce supply of organic nutrients. When 'deep' means deeper than 1000 m, these biotopes include more than half (~6 2 % ) of the volume of the global biosphere (Jannasch and Taylor, 1984). The average pressure on the ocean floor is of the order of 38 MPa, indicatCorrespondence to R. Jaenicke,

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“…14- 16 The volume changes for the working electrode reaction (DV complex ) were determined by subtracting DV ref (29 (4)). These results are collected in Table 3 and may be separated into contributions from intrinsic and electrostrictive effects.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…29 Temperature dependent spectra were measured on a Perkin-Elmer Lambda 12 spectrophotometer, fitted with a Peltier temperature controller.…”

Section: Electronic Spectroscopymentioning

confidence: 99%

Pressure and temperature effects on metal-to-metal charge transfer in cyano-bridged Co^III–Fe^IIcomplexes

et al. 2005

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The effects of pressure and temperature on the energy (E op ) of the metal-to-metal charge transfer ( (where L 14 = 6-methyl-1,4,8,11-tetraazacyclotetradecan-6-amine) were examined. The changes in the redox potentials of the cobalt and iron metal centres with pressure and temperature were also examined and the results interpreted with Marcus-Hush theory. The observed redox reaction volumes can mainly be accounted for in terms of localised electrostriction effects. The shifts in E op due to both pressure and temperature were found to be less than the shifts in the energy difference (

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Compact, transportable, and multipurpose high-pressure unit for UV–VIS spectroscopic measurements at pressures up to 200 MPa

Cited by 89 publications

References 1 publication

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

Proteins under pressure

Pressure and temperature effects on metal-to-metal charge transfer in cyano-bridged Co^III–Fe^IIcomplexes

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Compact, transportable, and multipurpose high-pressure unit for UV–VIS spectroscopic measurements at pressures up to 200 MPa

Cited by 89 publications

References 1 publication

Mechanistic Information on CuII Metalation and Transmetalation of Chlorophylls

Mechanistic Information on CuII Metalation and Transmetalation of Chlorophylls

Proteins under pressure

Pressure and temperature effects on metal-to-metal charge transfer in cyano-bridged CoIII–FeIIcomplexes

Contact Info

Product

Resources

About

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

Mechanistic Information on Cu^II Metalation and Transmetalation of Chlorophylls

Pressure and temperature effects on metal-to-metal charge transfer in cyano-bridged Co^III–Fe^IIcomplexes