Electron Spin Resonance Investigations of Ultra-violet and X-irradiated Bovine Serum Albumin

Koch, R.; Mönig, H.

doi:10.1038/203859a0

Cited by 13 publications

(3 citation statements)

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“…Studies of photo‐processes in proteins and amino acids show that by using EPR (electron paramagnetic resonance), spectrophotometry and luminescence measurements it is possible to investigate the kinetics of reactions at room temperature and low temperatures and also the structures of initial products . Using these methods it was found that UV‐irradiation of dry protein powders and protein solutions results in the formation of free radicals, namely in residues of aromatic amino acids and cysteine …”

Section: Introductionmentioning

confidence: 99%

“…21 Using these methods it was found that UV-irradiation of dry protein powders and protein solutions results in the formation of free radicals, namely in residues of aromatic amino acids and cysteine. [23][24][25] Sulfur amino acids are of high interest due to the well-known roles of disulfide bonds and sulfhydryl groups in the structure of proteins. In addition, early observations showed that photolytic end products of proteins originate at disulfide bonds or sulfhydryl groups.…”

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confidence: 99%

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Effect of UV-Radiation on the Packaging-Related Properties of Whey Protein Isolate Based Films and Coatings

Schmid

Held

Hammann

et al. 2015

Packag. Technol. Sci.

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The high oxygen barrier properties of whey protein based films and coatings means these materials are of great interest to the food and packaging industry. However, these materials have poor mechanical properties such as the tensile strength, Young's modulus and elongation at break. Up until now, the influence of ultraviolet (UV) radiation on whey protein films has not been reported in the literature. This study thus investigates the influence of UV-radiation on the properties of whey protein based films. UV-irradiated films showed increased tensile strength and a yellowing that was dependent on the radiation time. After irradiation, the films showed no significant change in the barrier properties, Young's modulus or elongation at break. In addition, a protein solubility study was undertaken to characterize and quantify changes in structure-property relationships. The significant decrease in protein solubility in buffer systems which break disulfide and non-covalent bonds indicates that additional molecular interactions arise with increasing radiation dose. This study provides new data for researchers and material developers to tailor the characteristics of whey protein based films according to their intended application and processing. and scientists are working hard to enhance the physical and barrier properties of protein films. According to Wihodo and Moraru, 1 the influence of film formulation and preparation conditions, plasticization, pH alteration, molecular weight adaption and lipid addition on the functional properties of protein films have been extensively investigated and discussed. To modify the properties of proteins, cross-linking techniques induced by heat, chemicals, enzymes and irradiation and the use of nanocomposites have been reported. 1,[9][10][11][12] The formation of covalent interactions such as intermolecular disulfide bonds (heat treatment), ε-(γ-glutamyl)-lysyl bonds (transglutaminase cross-linking) and covalent cross-links between aromatic acids (Ultraviolet (UV) radiation) lead to stabilization of the polymer network and are therefore essential for the mechanical and barrier properties. 13 Recently completed research projects showed that existing whey protein formulations are suitable as barrier layers. [8][9][10]14,15 The influence of UV-radiation on the functional properties and the structureproperty relationships now need to be investigated.According to literature, some research groups 1,7,16-20 have already worked on UV-irradiated protein-based films. Ustunol and Mert 19 irradiated whey protein solution for 3 h with UV light and described increased tensile strength of the cast films but there was no significant difference in the oxygen and water vapour barriers. However, no publications can be found on the influence of UV-irradiation on cast whey protein films.The objective of this study was to investigate if and to what extent the whey protein based barrier layers are influenced by UV irradiation, namely the irradiation time [min] and radiation dose [J/m 2 ]. Of particular inter...

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Effect of UV-Radiation on the Packaging-Related Properties of Whey Protein Isolate Based Films and Coatings

Schmid

Held

Hammann

et al. 2015

Packag. Technol. Sci.

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“…This assumption is supported by comparative investigations on crystalline trypsin (Brustad et al, 1966) and bovine serum albumin (Koch and M6nig, 1964) after exposure with ionizing radiation or ultraviolet light. Therefore, additional electrons are absent, thus leading to a lower yield of sulfur radical anions.…”

Section: Discussionmentioning

confidence: 87%

Investigations on radical formation and inactivation of suspended trypsin after?-irradiation

Mönig

1977

Radiat Environ Biophys

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Crystalline trypsin was irradiated in oxygen-free suspension media of methanol, ethanol and n-heptane with 60Co-gamma-rays at 77 K or 273 K. Measurements with ESR and activity determinations revealed no influence of ethanol and n-heptane on the formation of free radicals and inactivation of trypsin. Especially, the results are independent on the polarity of the suspension media and correspond to an irradiation of trypsin in vacuum. On the other hand, methanol leads to a decay of radiation induced radicals and to an increased inactivation. The results are discussed in comparison to analogous experiments carried out with ultra-violet light.

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Radiation Effects on Biomembranes

Wallach

1974

Biomembranes

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Electron Spin Resonance Investigations of Ultra-violet and X-irradiated Bovine Serum Albumin

Cited by 13 publications

References 3 publications

Effect of UV-Radiation on the Packaging-Related Properties of Whey Protein Isolate Based Films and Coatings

Effect of UV-Radiation on the Packaging-Related Properties of Whey Protein Isolate Based Films and Coatings

Investigations on radical formation and inactivation of suspended trypsin after?-irradiation

Radiation Effects on Biomembranes

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