Related Experiment Video
Updated: Aug 15, 2026

Collecting Variable-concentration Isothermal Titration Calorimetry Datasets in Order to Determine Binding Mechanisms
Published on: April 7, 2011
Spectrophotometric titration of ionisable groups in proteins: a theoretical study
M Miteva1, A Shosheva, B Atanasov
1Biophysical Chemistry Laboratory, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia. miteva@orgchm.bas.bg
Abstract:
A simple theoretical model is proposed for evaluation of the optical titration behaviour of tyrosyl and carboxyl residues in proteins. The pK values involved in the model are computed using the semi-empirical method. The titration curves are calculated using the values of the molar absorption differences for tyrosyl residues in the ultraviolet (UV) region at 245 and 295 nm, and for carboxyl residues in the infrared (IR) region at 1565 and 1707 cm(-1), respectively. The theoretical tyrosyl titration curves are compared with the experimental data for lysozyme, myoglobin and chymotrypsinogen (available in the literature). This approach provides a good tool for distinguishing between the ionisation and the conformational changes in the alkaline range. The quantitative evaluation of the change of molar extinction coefficients as a function of pH in the case of carboxyl titration for lysozyme, trypsin and cytochrome c shows a good agreement with the experimental titration data.
More Related Videos
10:03Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
11:38Quantifying the Binding Interactions Between Cu(II) and Peptide Residues in the Presence and Absence of Chromophores
Published on: April 5, 2022
Related Concept Videos
Titrimetric Methods: Types and Commonly Used Strategies
Classification of Titrimetric Analysis Based on Reaction Types
Titrations between an acid and a base lead to neutralization reactions that form...
Titration in Nonaqueous Solvents
Potentiometric Titration: Overview
Complexometric Titration: Overview
EDTA: Indirect and Alkalimetric Titration