pH titration of native and unfolded ß-trypsin: evaluation of the D D G0 titration and the carboxyl pK values

Brazilian Journal of Medical and Biological Research

A.r. Günther²  M.m. Santoro¹  E. Rogana¹ 

[1] ,Universidade Federal de Santa Catarina

关键词: ß-trypsin;    protein stability;    protein pH titration;   

DOI  :  10.1590/S0100-879X1997001100003

来源: SciELO

【 摘 要 】

The stabilizing free energy of ß-trypsin was determined by hydrogen ion titration. In the pH range from 3.0 to 7.0, the change in free energy difference for the stabilization of the native protein relative to the unfolded one (D D G0 titration) was 9.51 ± 0.06 kcal/mol. An isoelectric point of 10.0 was determined, allowing us to calculate the Tanford and Kirkwood electrostatic factor w. This factor presented a nonlinear behavior and indicated more than one type of titratable carboxyl groups in ß-trypsin. In fact, one class of carboxyl group with a pK = 3.91 ± 0.01 and another one with a pK = 4.63 ± 0.03 were also found by hydrogen ion titration of the protein in the folded state

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License