Terahertz time-domain and FTIR spectroscopic study of interaction of α-chymotrypsin and protonated tris with 18-crown-6

Chymotrypsin activity in nonaqueous solvents increases in the presence of crown-ethers, presumably, due to the interaction of crown-ether molecules with surface amino-groups of protein. FTIR and THz-TDS spectroscopic techniques are used to study the interaction of crown-ether with chymotrypsin and protonated tris(hydroxymethyl)aminomethane, which serves as a model of the amino-groups of protein. Spectra measured at different relative molar concentrations indicate the interaction of the components. The spectral changes and variations in the absolute values of the absorption coefficient are discussed. The similarity of the spectral changes is demonstrated for protein-crown–ether and tris-crown–ether samples.