Hydrogen exchange rate

The number of NMR parameters available for measurement is rather small, consisting of the chemical shift, relaxation rates (/1 and lo), scalar (J) couplings, dipolar (D) couplings, cross-relaxation rates (the NOE), and hydrogen exchange rates. All of these have been quantified for many of the amide protons of A131 A, and most of the data suggest the presence of little persistent structure. 

Amide proton temperature coefficients and hydrogen exchange rates can provide information about hydrogen-bonding interactions and solvent sequestration in unfolded or partly folded proteins (Dyson and Wright, 1991). Abnormally low temperature coefficients, relative to random coil values, are a clear indication of local structure and interactions. 

Relative Hydrogen Exchange Rates with Bases and Acids... 

V. Comparison of Hydrogen Exchange Rates in Liquid Ammonia and in other... 

VI. Unusual Relation between Hydrogen Exchange Rates in Protophilic and... 

A. Effect of the Charge of the Substrate on the Hydrogen Exchange Rate... 

Fig. 2.4. Hydrogen exchange rate profile for heteroaromatic compound with multiple basic centers.

Fig. 2.6. Experimental hydrogen exchange rate profile for 4-pyridone/4-hydroxypyridine.

Fig. 2.8. Idealized hydrogen exchange rate profile for deuteriation of l-hydroxy-2,6-di-methyl-4-pyridone.

Hydrogen-exchange rates as a function of level of hydration can be calculated from data such as those of Fig. 22. Results of this kind, for pH 2-10, are given in Fig. 23. The slope of the exchange rate-water... 

Fig. 23. Dependence on log water activity of log ratio of powder to solution amide hydrogen exchange rate for lysozyme. Log rate ratio data for pH 2 (bottom) to pH 10 (top) are given as a function of log(/ /Po). The slopes of the lines give the order of the protein exchange reaction with respect to water. The slopes from least-squares linear regression are the following pH 2, 2.57 pH 3, 2.90 pH 5, 3.14 pH 7, 3.14 and pH 10, 2.53. Displacement along the log rate ratio axis is arbitrary. Numbers indicate some of the H m values for which rate ratios were determined. From Schinkel et at. (1985).

Kim, K.-S. Woodward, C. (1993). Protein internal flexibility and global stability Effect of urea on hydrogen exchange rates of bovine pancreatic trypsin inhibitor. Biochemistry 32,9609-9613. Kuwajima, K., Nitta, K., Yoneyama, M. Sugai, S. (1976). Three-state denaturation of o-lactalbumin by guanidine hydrochloride. J. Mol. Biol. 106, 359-373. 

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