Globular proteins undergo structural transitions to denatured states when sufficient thermodynamic state or chemical perturbations are introduced to their native environment. Cold denaturation is a somewhat counterintuitive phenomenon whereby proteins lose their compact folded structure as a result of a temperature drop. The currently accepted explanation for cold denaturation is based on an as...

Of the different kinds of denaturation of proteins, that by heat has been investigated most thoroughly. The theory has been put forward that the loss of the zwitter ion structure by an interaation of the ionogenic groups is the most important of the electrochemical changes which a protein undergoes by the action of heat (Pauli (6), Cohn (2)). The question as to whether other structural changes ...

The coagulation of proteins has been shown to consist of two distinct processes (2, 3). In the first of these the protein is denatured, and in the second the denatured protein is agglutinated or flocculated. Chick and Martin (3) and more recently Lepeschldn (4) have investigated these two processes separately, and it is to them that we owe much of our knowledge in this field. Most of the work h...

We study cold denaturation of proteins at high pressures. Using multicanonical Monte Carlo simulations of a model protein in a water bath, we investigate the effect of water density fluctuations on protein stability. We find that above the pressure where water freezes to the dense ice phase (approximately 2 kbars) the mechanism for cold denaturation with decreasing temperature is the loss of lo...

The kinetics of thermal denaturation of ceruloplasmin in water and in water with different percentage of D2O in the temperature range 25-85 degrees C, following the optical density change of the 610 nm charge transfer band of the protein has been investigated. A temperature Tt approximately equal to 65 degrees C above which an irreversible denaturation process of the protein active site takes p...

Pacu ( Piaractus mesopotamicus ) is one of the most important fish farmed species in Brazil due to its hardy, fast growing, omnivorous feeding behavior, and good consumers acceptance. However, studies on effect different slaughtering procedures quality frozen pacu fillets have not been carried out. Therefore, this study aimed evaluate electrical stunning, CO 2 narcosis, or water/ice immersion (...

Macromolecular crowding ought to stabilize folded forms of proteins, through an excluded volume effect. This explanation has been questioned and observed effects attributed to weak interactions with other cell components. Here we show conclusively that protein stability is affected by volume exclusion and that the effect is more pronounced when the crowder's size is closer to that of the protei...