Ver�nderung von Aminos�uren und Aktivit�t bei R�ntgenbestrahlung von krystallisiertem Lysozym

Dose, Klaus; Risi, S.; Rauchfuss, Horst

doi:10.1007/bf01191613

Cited by 11 publications

(4 citation statements)

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“…For example, sparking mixtures of H 2 , H 2 O, NH 3 or N 2 or CO or CH 4 and CO 2 produces urea [3,4]. In addition, the irradiation with protons [5], beta rays [6], and X rays [7] yield urea from a mixtures of gases (methane, ammonia, and water). It is also easily synthesized from the irradiation of hydrogen cyanide (HCN) in a liquid or solid state [8].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

et al. 2014

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Abstract:Urea is an organic molecule present in most living organisms. Historically, it was the first organic molecule synthesized in the laboratory. In prebiotic chemistry, urea readily forms in different laboratory simulations using different energy sources. Furthermore, the role of solid surfaces, particularly minerals, might have been crucial to increase the complexity of the organic matter which may have led to the subsequent emergence of life on Earth.In this work, the radiolysis of urea in presence of a clay is studied to determine to what extent the mineral surfaces influence the decomposition of organics. The results indicate that urea is relatively stable to ionizing radiation in aqueous solutions and up to 20 kGy no decomposition is observed. Moreover, the presence of sodium montmorillonite, by a mechanism until now unknown, affects the radiolytic behavior and urea remains in the heterogeneous solution without a change in concentration even at very high doses (140 kGy). These results indicate that solids could have protected some organics, like urea, from degradation enabling them to remain in the environment on the primitive Earth.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

et al. 2014

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Section: H+h -Hzmentioning

confidence: 99%

“…It is instructive to compare the very large doses needed for inactivation of the enzyme by ionization in the crystal with the extremely high efficiency observed in radical attack by H atoms, and also OH radicals [6,7], in aqueous solution. In the crystalline form, doses of the order of 100 Mrads were needed to obtain sufficient effect for amino acid analysis (16) and the damage was more diffuse. Nevertheless it is apparent that the divalent sulphur and aromatic amino acids predominated among those affected.…”

Section: H+h -Hzmentioning

confidence: 99%

“…The radiation chemistry of lysozyme has also been investigated in the solid crystalline form [15,16]. Dose, Risi and Rauchfuss [16] have carried out an amino acid analysis on the treated samples. It is instructive to compare the very large doses needed for inactivation of the enzyme by ionization in the crystal with the extremely high efficiency observed in radical attack by H atoms, and also OH radicals [6,7], in aqueous solution.…”

Section: H+h -Hzmentioning

confidence: 99%

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The Role of Tryptophan and Divalent Sulphur in the Action of Atomic Hydrogen on Lysozyme in Aqueous Solution

Aldrich

Cundall

Lanier

et al. 1970

Israel Journal of Chemistry

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The effect of atomic hydrogen on lysozyme in aqueous solution has been investigated at different pH, total doses of H atoms and different initial concentrations. As well as inactivation, changes in the ultra violet absorption spectrum, due to tryptophan, formation of sulphydryl groups and H2S, associated with attack on disulphide bonds, have been measured. The decrease in the 280 nm absorption is consistent with attack on the tryptophan residues. Intramolecular transfer of the free radical centre is assumed. The effect of increasing enzyme concentration shows that the intramolecular radical chain terminates when the odd electron becomes paired by encounter with another lysozyme radical. As found for trypsin, the formation of H2S is less when tryptophan as well as tyrosine is present in the enzyme.

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Lysozyme: Ein Kapitel Molekularbiologie

Jollès

1969

Angewandte Chemie

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Ver�nderung von Aminos�uren und Aktivit�t bei R�ntgenbestrahlung von krystallisiertem Lysozym

Cited by 11 publications

References 10 publications

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

The Role of Tryptophan and Divalent Sulphur in the Action of Atomic Hydrogen on Lysozyme in Aqueous Solution

Lysozyme: Ein Kapitel Molekularbiologie

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