The reversible denaturation of protein disulfide isomerase proceeds through intermediates that are stabilized by interaction with guanidine hydrochloride. At pH 7.5, the equilibrium denaturation by urea is completely reversible and the transition can be reasonably well-described by a two-state model involving only native and denatured forms. In comparison, the equilibrium denaturation by guanid...

Thermal processing often results in disruption of the native conformation of whey proteins, thus affecting functional properties. The aim of this work was to evaluate the effects of moderate electric fields on denaturation kinetics and thermodynamic properties of whey protein dispersions at temperatures ranging from 75 to 90 °C. Application of electric fields led to a lower denaturation of whey...

To increase our understanding of the physical nature of the Na+ and K+ forms of the Na+ + K+-dependent ATPase, thermal-denaturation studies were conducted in different types of ionic media. Thermal-denaturation measurements were performed by measuring the regeneration of ATPase activity after slow pulse exposure to elevated temperatures. Two types of experiments were performed. First, the depen...

The combination of deuterium-hydrogen exchange (DHX) and mass spectrometry (MS) can be used for studying a high pressure denaturation (HPD) of proteins. Herein we present the results of investigations of the influence of glycation on the HPD of ubiquitin. Application of various values of pressure causes different degrees of protein unfolding, resulting in molecules with a different number of pr...

MNEI is a single chain derivative of monellin, a plant protein that can interact with the human sweet taste receptor, being therefore perceived as sweet. This unusual physiological activity makes MNEI a potential template for the design of new sugar replacers for the food and beverage industry. Unfortunately, applications of MNEI have been so far limited by its intrinsic sensitivity to some pH ...

Fragment-based lead discovery has proved to be an effective alternative to high-throughput screenings in identifying chemical matter that can be developed into robust lead compounds. The search for optimal combinations of biophysical techniques that can correctly and efficiently identify and quantify binding can be challenging due to the physicochemical properties of fragments. In order to mini...

Two-dimensional infrared correlation spectroscopy (2D-IR) was applied to the study of urea- and heat-induced unfolding denaturation of sarcoplasmic reticulum Ca(2+)-ATPase (SR ATPase). Urea at 2-3 M causes reversible loss of SR ATPase activity, while higher concentrations induce irreversible denaturation. Heat-induced denaturation is a non-two-state process, with an "intermediate state" (at t a...

Although the thermodynamics of protein denaturation at temperatures over 100 °C is essential for the rational design of highly stable proteins, it is not understood well because of the associated technical difficulties. We designed certain hydrophobic mutant proteins of CutA1 from Escherichia coli, which have denaturation temperatures (Td) ranging from 101 to 113 °C and show a reversible heat d...

Bio-fuel cells are alternative energy devises based on bio-electrocatalysis of natural substrates by enzymes or microorganisms. Here we review bio-fuel cells and bio-batteries based on the recent literature. In general, the bio-fuel cells are classified based on the type of electron transfer; mediated electron transfer and direct electron transfer or electronic charge transfer (ECT). The ECT of...