Renaturation of Myoglobin Denatured by Sodium Dodecyl Sulfate by Removal of Dodecyl Sulfate Ions Bound to the Protein Using Sodium Cholate.

The secondary and tertiary structures of myoglobin were disrupted by sodium dodecyl sulfate (SDS) but were hardly affected by the bile salt, sodium cholate (NaCho). This disruption was induced by the binding of dodecyl sulfate (DS) ions to the protein. In this study, the removal of DS ions bound to the protein was attempted using NaCho.

Removal of Dodecyl Sulfate Ions Bound to Human and Bovine Serum Albumins Using Sodium Cholate.

The secondary structures of human serum albumin (HSA) and bovine serum albumin (BSA) were disrupted in the solution of sodium dodecyl sulfate (SDS), while being hardly damaged in the solution of the bile salt, sodium cholate (NaCho). In the present work, the removal of dodecyl sulfate (DS) ions bound to these proteins was attempted by adding various amounts of NaCho. The extent of removal was estimated by the restoration of α-helical structure of each protein disrupted by SDS.

Secondary Structural Changes of Intact and Disulfide Bridges-Cleaved Human Serum Albumins in Thermal Denaturation up to 130°C - Additive Effects of Sodium Dodecyl Sulfate on the Changes.

The secondary structural changes of human serum albumin with the intact 17 disulfide bridges (HSA) and the disulfide bridges-cleaved human serum albumin (RCM-HSA) in thermal denaturation were examined. Most of the helical structures of HSA, whose original helicity was 66%, were sharply disrupted between 50 and 100°C. However, 14% helicity remained even at 130°C.

Kinetic Aspects of Surfactant-Induced Structural Changes of Proteins - Unsolved Problems of Two-State Model for Protein Denaturation -.

The kinetic mechanism of surfactant-induced protein denaturation is discussed on the basis of not only stopped-flow kinetic data but also the changes of protein helicities caused by the surfactants and the discontinuous mobility changes of surfactant-protein complexes. For example, the α-helical structures of bovine serum albumin (BSA) are partially disrupted due to the addition of sodium dodecyl sulfate (SDS). Formation of SDS-BSA complex can lead to only four complex types with specific mobilities depending on the surfactant concentration.

Secondary structural changes of homologous proteins, lysozyme and α-lactalbumin, in thermal denaturation up to 130 °C and sodium dodecyl sulfate (SDS) effects on these changes: comparison of thermal stabilities of SDS-induced helical structures in these proteins.

The thermal stability of two homologous proteins, lysozyme and α-lactalbumin, was examined by circular dichroism. The present study clearly showed two different aspects between the homologous proteins: (1) the original helices of lysozyme and α-lactalbumin were unchanged at heat treatments up to 60 and 40 °C, respectively, indicating a higher thermal stability of lysozyme, and (2) upon cooling to 25 °C, the original helices of lysozyme were never reformed after they were once disrupted, while those of α-lactalbumin, disrupted at a particular temperature range between 40 and 60 °C, were completely reformed. In addition, the structural changes were also examined in the coexistence of sodium dodecyl sulfate (SDS), which induced the formation of helical structures in these proteins at 25 °C.

Protein structural change in a mixed system of ionic and zwitterionic surfactants.

The secondary structure of bovine serum albumin (BSA) in the binary surfactant system of anionic sodium dodecyl sulfate (SDS) and zwitterionic N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DDAPS) was examined at 25°C. The helicity of BSA decreased from 66% to 55% in a solution of DDAPS alone and decreased to 50% in a solution of SDS alone. However, the late addition of DDAPS reformed the helical structure of BSA, which was initially disrupted by SDS.

Critical temperature of secondary structural change of myoglobin in thermal denaturation up to 130 degrees C and effect of sodium dodecyl sulfate on the change.

The secondary structural change of horse heart myoglobin was examined in the thermal denaturation up to 130 degrees C. The original helicity of 82% gradually decreased to 67% with rise of temperature until 75 degrees C. Thereafter, it suddenly decreased to 24% at 90 degrees C and then slightly decreased to 14% at 130 degrees C.

Protective effect of gemini surfactant on secondary structural change of bovine serum albumin in thermal denaturation up to 130 degrees C.

The effect of gemini surfactant, sodium dilauramidoglutamide lysine (DLGL), on the secondary structure of bovine serum albumin (BSA) was examined at 25 degrees C and at high temperatures up to 130 degrees C. The helicity (66%) of the protein decreased to 53% in the DLGL solution at 25 degrees C and it also decreased to 16% with rise of temperature. Although approximately half of the original helical structures were destroyed upon heating up to 75 degrees C, most of the structures were maximally protected in the coexistence of 0.

Immunochromatographic assay using gold nanoparticles for measuring salivary secretory IgA in dogs as a stress marker.

The concentration of salivary secretory immunoglobulin A (sIgA) is a well-known stress marker for humans. The concentration of salivary sIgA in dogs has also been reported as a useful stress marker. In addition, salivary sIgA in dogs has been used to determine the adaptive ability of dogs for further training.

Secondary structural change of bovine serum albumin in thermal denaturation up to 130 degrees C and protective effect of sodium dodecyl sulfate on the change.

The secondary structure of bovine serum albumin (BSA) was first examined in the thermal denaturation up to 130 degrees C. The helicity (66%) of the protein decreased with rise of temperature. Half of the original helicity was lost at 80 degrees C, but the helicity of 16% was still maintained even at 130 degrees C.

Protective effect of small amounts of sodium dodecyl sulfate on the helical structure of bovine serum albumin in thermal denaturation.

In the presence of sodium dodecyl sulfate (SDS), the secondary structure of bovine serum albumin (BSA) was almost protected against thermal denaturation above 50 degrees C, where the structural change became irreversible. Beyond 30 degrees C, the helicity (66%) of the protein sharply decreased with rise of temperature. In response to this, the proportions of beta-structure and random coil increased.

Protective effects of small amounts of bis(2-ethylhexyl)sulfosuccinate on the helical structures of human and bovine serum albumins in their thermal denaturations.

The protective effect of an anionic double-tailed surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT), on the structures of human serum albumin (HSA) and bovine serum albumin (BSA) in their thermal denaturations was examined by means of circular dichroism measurements. The structural changes of these albumins were reversible in the thermal denaturation below 50 degrees C, but became partially irreversible above this temperature. The effect was observed in the thermal denaturation above 50 degrees C.