Thermal denaturation kinetics

Hinrichs, J. and Rademacher, B. 2004. High pressure thermal denaturation kinetics of whey proteins. J. Dairy Res. 71(4) 480-488. 

In an analogous way the influence of alcohol on the kinetics of thermal denaturation of met-hemoglobin was studied successfully144). 

Prostatic acid phosphatase is partially and reversibly inactivated by calcium ion (45). Anions such as chloride, bromide, and thiocyanate inhibit prostatic acid phosphatase competitively with regard to substrate as well as noncompetitively. A kinetic analysis by London et al. (46) indicates that the noncompetitive inhibition was related to changes in charge on the protein molecule. A variety of nonspecific anions accelerate thermal denaturation of the enzyme. The enzyme is quite sensitive to a number of electrolyte changes, but it is not clear whether these factors are involved in biological control. 

The presence of ions not only affects canonical base pairs [22], but promotes the formation of triplexes and other non-canonical DNA structures [23]. The effects of these interactions span from modifications of the renaturation kinetics of thermally denaturated DNA [24] to the known anti-tumoral and mutagenic activity of cisplatin [25]. 

Plock, J., Spiegel, T., and Kessler, H.G. (1997). Reaction kinetics of the thermal denaturation of whey protein in sweet whey concentrated by evaporation. Milchwissenschaft 53, 327-331. 

The small effect of these tsf substitutions on the first kinetic phase for thermal unfolding explains why they have hardly any effect on the melting temperature. Unfolding of the N-terminal region of the molecule is the initiation step for thermal denaturation of this protein. The apparent Tm measured by microcalorimetry could be defined by this step. Given their location in the central region of the chain, it is not surprising that the tsf mutant proteins affect the second step but not the first. 

Tessier, H., and Rose, D. (1958). Calcium ion concentration in milk. /. Dairy Sd. 41,351-359. Tolkach, A., and Kulozik, U. (2005). Effect of pH and temperature on the reaction kinetic parameters of thermal denaturation of -lactoglobultn. Milchwissenschaft 60,... 

T. Le Bihan and C. Gicquaud, Kinetic study of the thermal denaturation of G actin using differential scanning calorimetry and intrinsic fluorescence spectroscopy, Biochem. Biophys. Res. Commun. 194, 1065-1073 (1993). 

Steady-state kinetics studies of the inhibition of the enzyme by oxR-mate and oxalate 203) hinted at the existence of enzyme-oxamate complexes. No binding of 0.15 milf oxamate was detected in the ultracentrifuge. However, Siidi 283) reported that oxalate (15 mM) and oxamate (60 mM) protect M4 enzyme from heat denaturation. Oxaloacetate and fructose 1,6-diphosphate are effective at protecting against thermal denaturation at 1 mM concentration 286). It is possible that these anions bind at sites similar to those detected in the dogfish M4 LDH molecule 139). 

Galisteo M L, Mateo P L, Sanchez-Ruiz J M (1991). Kinetic study on the irreversible thermal denaturation of yeast phosphoglycerate kinase. Biochem. 30(8) 2061-2066. 

In contrast to Me cyts bs, the thermodynamic equilibrium ratio of A B isomers of 1 1.3 in OM cyt bs favors isomer B, and is obtained only after hours at 65 °C. At physiological temperature, the OM cyt bs heme is kinetically trapped. Several other properties of rat OM cyt bs differ from those of rat Me cyt bs. - (i) OM cyt bs has a significantly lower redox potential than Me cyt bs (Table 2) (ii) OM cyt bs T, 83.6 °C) is more stable toward thermal denaturation than Me cyt bs (7m, 65.2 °C). (iii) OM cyt bs is about lOkJmol ( 2.5kcalmol ) more stable than Me cyt bs towards chemical denaturation (iv) while bovine Me cyt bs will release heme to apo-myo obin at pH 7.0, heme is not transferred from rat OM cyt bs to apo-myoglobin even at pH values as low as 5.2. Two hydrophobic networks responsible for the stability and slow heme dissociation and reorientation in OM cyt bs have been identified. Mutation of the five residues involved in these hydrophobic networks in OM cyt bs yields a protein with the structural elements of Me cyt bs Molecular dynamics simulations predict two conformers of Me cyt bs in solution, a cleft-open and a cleft-closed form and only one, the cleft-closed form, for OM cyt Z>5.3 2 394 is proposed that OM cyt bs is held in the cleft-closed conformation by one of its hydrophobic networks. 

Skelte, G.A. Anthony B.M. Reaction kinetics of thermal denaturation of whey proteins in heated Reconstituted whole milk. Journal of Agricultural and Food Chemistry, 1996, 44,422-428. 

AI Hohlberg. Kinetics of bean protein thermal denaturation. J Food Process Preserv ii 31-42 (1987). 

ISOTOPIC EFFECTS ON THE KINETICS OF THERMAL DENATURATION OF MET-HEI40GL0BIN... 

We studied the effects of total and partial deuteration on the kinetics of thermal denaturation of met-hemoglobin. The kinetics were shown to be first order with respect to protein concentration this was true both in H2O and in D2O within the entire range of temperatures examined. Deuterium oxide increased the stability of the native conformation of met-hemoglobin this effect increased progressively by increasing the amount of D2O in the solution. Extension of the experiments to the amplest possible temperature range (50-63°C) allowed the determination of the isotopic effect on the activation enthalpy and entropy of the denaturation reaction the isotopic effect resulted to be mainly entropic. 

---