A comparative study on the aggregating effects of guanidine thiocyanate, guanidine hydrochloride and urea on lysozyme aggregation

Emadi, Saeed; Behzadi, Malihe

doi:10.1016/j.bbrc.2014.06.133

Cited by 22 publications

(21 citation statements)

References 19 publications

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“…For preparation of AFM samples, 10 μl of each sample was loaded onto a mica surface and allowed to fix on mica by incubation for 30 minutes at room temperature. The mica surface was then washed once with 100 μl deionized water and left to dry at room temperature before being examined by the atomic force microscope [ 39 ].…”

Section: Methodsmentioning

confidence: 99%

Unraveling the novel effects of aroma from small molecules in preventing hen egg white lysozyme amyloid fibril formation

et al. 2018

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This study investigated for the first time the molecular effectiveness of 'aroma' from three small molecules including a phenol (phenyl ethyl alcohol; PEA) and an aldehyde (cinnamaldehyde; Cin) both containing an aromatic ring, and a diamine (N,N,N,N'- Tetramethylethylenediamine; TEMED) at two different amounts (small; S and large; L) in preventing hen egg white lysozyme (HEWL) amyloid fibril formation using Thioflavin T and Nile red fluorescence assays, circular dichroism spectroscopy, SDS-polyacrylamide gel electrophoresis, atomic force microscopy, dynamic light scattering and HEWL activity test. Interestingly, the results revealed that (1) the aroma of PEA, identified as an active constituent of Rosa damascena, prevented fibril formation since PEA-L was able to trap the oligomeric form of HEWL in contrast to PEA-S where protofibrils but not mature fibrils were formed; (2) Cin, previously shown to prevent fibril formation in the liquid form, was also shown to do so in the aroma form by producing protofibrils and not mature fibrils in both Cin- L and Cin-S aroma forms and (3) the aroma of TEMED-L was able to retain HEWL’s native structure completely and prevented both aggregation and fibril formation, while TEMED-S prevented HEWL fibril formation and instead directed the pathway towards amorphous aggregate formation. Furthermore, the ability to trap oligomeric species (by PEA-L aroma) is of great importance for further research as it provides routes for preventing the formation of toxic oligomeric intermediates along the fibrillation pathway. Last but not least, the novelty of this in vitro study on the effect of aroma at the molecular level with a unique experimental set-up using HEWL as a model protein in assessing amyloid fibril formation paves the way for more and detailed studies on the importance of aroma producing molecules and their effects.

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Section: Methodsmentioning

confidence: 99%

Unraveling the novel effects of aroma from small molecules in preventing hen egg white lysozyme amyloid fibril formation

et al. 2018

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“…Despite this finding, previous studies demonstrated that urea inhibited lysozyme activity (Sidhan, 1982;Bazrkar and Aghamaali, 2015). On the other hand, in another study on the effects of three different denaturants, guanidine thiocyanate, guanidine hydrochloride and urea, it has been observed that urea had the lowest effect on enzyme activity (Emadi and Behzadi, 2014).…”

Section: Notementioning

confidence: 95%

Biochemical characterisation of lysozyme extracted from rainbow trout Oncorhynchus mykiss (Walbaum, 1792)

2021

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In the present study, lysozyme was extracted from spleen tissue of rainbow trout Oncorhynchus mykiss (Walbaum, 1792) and partially purified by ammonium sulfate precipitation. Optimum pH and temperature as well as effects of different salt concentrations of NaCl, MgCl 2 , KCl and urea on enzyme activity were evaluated. The enzyme activity was assayed using a suspension of Micrococcus lysodeikticus as substrate. Results showed that lysozyme extracted from the spleen of O. mykiss has its optimum activity at high temperature (60ºC) and low pH (5.8) conditions and the enzyme activity was found to vary with different salt concentrations which were found related to the environmental conditions of natural habitats of O. mykiss.

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“…In the presence of SDS (0.0 to 0.6 mM), fibril formation occurs over a broad pH range (1.0 to 10.0), but most pronounced at pH 1.0 (Khan et al., ). Emadi and Behzadi () reported that incubation of LYS at pH 7.0 in 4.0 M guanidine hydrochloride or 1.0 to 2.0 M guanidine thiocyanate yields structures that exhibit ThT fluorescence, although no clear fibril formation is detected.…”

Section: Hen Egg Proteinsmentioning

confidence: 99%

Conditions Governing Food Protein Amyloid Fibril Formation—Part I: Egg and Cereal Proteins

Jansens

Lambrecht

Rombouts

et al. 2019

Comp Rev Food Sci Food Safe

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Conditions including heating mode, time, temperature, pH, moisture and protein concentration, shear, and the presence of alcohols, chaotropic/reducing agents, enzymes, and/or salt influence amyloid fibril (AF) formation as they can affect the accessibility of amino acid sequences prone to aggregate. As some conditions applied on model protein resemble conditions in food processing unit operations, we here hypothesize that food processing can lead to formation of protein AFs with a compact cross β‐sheet structure. This paper reviews conditions and food constituents that affect amyloid fibrillation of egg and cereal proteins. While egg and cereal proteins often coexist in food products, their impact on each other's fibrillation remains unknown. Hen egg ovalbumin and lysozyme form AFs when subjected to moderate heating at acidic pH separately. AFs can also be formed at higher pH, especially in the presence of alcohols or chaotropic/reducing agents. Tryptic wheat gluten digests can form fibrillar structures at neutral pH and maize and rice proteins do so in aqueous ethanol or at acidic pH, respectively.

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A comparative study on the aggregating effects of guanidine thiocyanate, guanidine hydrochloride and urea on lysozyme aggregation

Cited by 22 publications

References 19 publications

Unraveling the novel effects of aroma from small molecules in preventing hen egg white lysozyme amyloid fibril formation

Unraveling the novel effects of aroma from small molecules in preventing hen egg white lysozyme amyloid fibril formation

Biochemical characterisation of lysozyme extracted from rainbow trout Oncorhynchus mykiss (Walbaum, 1792)

Conditions Governing Food Protein Amyloid Fibril Formation—Part I: Egg and Cereal Proteins

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