By investigating the sulfhydryl groups of the muscle proteins I have attempted to throw some light on the state of the proteins in muscle and on the change in state of these proteins in muscular contraction. In previous papers i t has been shown that in a denatured protein the number of active SH groups is equivalent to the quantity of cysteine found in the hydrolyzed protein (Mirsky and Anson,...

BSA solution and the buffer used as a solvent, A is the area of the V = f(T) plot obtained for a given step of the considered thermal denaturation process and a is the part of this surface corresponding to a given temperature T. In this study some conformational changes induced by thermal denaturation of BSA macromolecule were evidenced, the temperatures of transition as well as the # G values ...

Listeriolysin O (LLO) is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is the only representative of cholesterol-dependent cytolysins that exhibits pH-dependent activity. Despite intense studies of LLO pH-dependence, this feature of the toxin still remains incompletely explained. Here we used fluorescence and CD spectroscopy to show that the stru...

By investigating the sulfhydryl groups of the muscle proteins I have attempted to throw some light on the state of the proteins in muscle and on the change in state of these proteins in muscular contraction. In previous papers i t has been shown that in a denatured protein the number of active SH groups is equivalent to the quantity of cysteine found in the hydrolyzed protein (Mirsky and Anson,...

Thrombin-activated porcine factor VIII (fVIIIaIIa) is a stable, active, 160-kDa heterotrimer at concentrations exceeding 2 x 10(-7) M in 0.7 M NaCl, 0.01 M histidine Cl, 5 mM CaCl2, pH 6.0, at 4 degrees C or 20 degrees C. Two of the subunits, fVIIIA1 and fVIIIA2, are derived from the heavy chain of the plasma-derived, heterodimeric fVIII precursor. The third subunit, fVIIIA3-C1-C2, is derived f...

A fragment of the starch-binding domain (SBDF) of Aspergillus niger glucoamylase was prepared using recombinant DNA techniques, and its thermal unfolding was investigated by high-sensitivity differential scanning calorimetry (DSC). Thermal unfolding of SBDF was found to be reversible at pH 7 as expected from a DSC study of the whole enzyme molecule [Tanaka A. et al., J. Biochem., 117, 1024-1028...

Unlike ferrihemoglobin (Hb+), denatured carbonylhemoglobin (COHb) has almost the same absorption spectrum in the visible and near ultraviolet region as the native form; the very slight difference’appears only in the Soret band. Kinetic and equilibrium experiments under anaerobic conditions show that COHb is considerably more resistant to acid denaturation at 25’ than is Hb+ although the rates o...

The thermal denaturation of ribonuclease A has been studied by use of Fourier transform nuclear magnetic resonance by monitoring the imidazole C-2 proton resonances of the histidine residues as a function of temperature at pH 1.3. As the temperature is raised, a slow chemical exchange process results in the disappearance of the peaks corresponding to the native conformation and the appearance o...