Determination of Structural and Thermodynamic Parameters of Bovine #-trypsin Isoform in Aqueous-Organic Media

Name: Dayanne Pinho RosaType: MSc dissertationPublication date: 23/02/2017Advisor:

Name	Role
Alexandre Martins Costa Santos	Advisor *

Examining board:

Name	Role
Alexandre Martins Costa Santos	Advisor *
Maria Aparecida Cicilini	External Examiner *
Patricia Machado Bueno Fernandes (M/D)	External Examiner *
Daniela Amorim Melgaço Guimarães do Bem	Internal Examiner *

Summary: Organic solvents are common in industrial processes that use enzymes but, at the same time, it is known that they change the properties thereof, thus the effects of aqueous-organic solvent (ethanol) in different concentration on the -trypsin structure have been investigated by spectroscopic techniques and thermodynamic data analysis. The results from spectroscopic measurements, including far-UV Circular Dichroism, UV-Vis absorption spectroscopy, intrinsic tryptophan fluorescence and dynamic light scattering (DLS) suggest the formation of partially folded states, dinstead of aggregates states, at high ethanol concentration (> 60% v/v ethanol), with little loss of secondary structure, but with significant tertiary structure changes. The thermodynamic data (Tm and H) suggest a loosen of intramolecular weak interactions, which reflects in a flexibility increase such that the catalytic capacity can be increased or decreased according to the ethanol concentration into the system.
Overall results we suggest that in range of 0-60% v/v ethanol/buffer, -trypsin
undergoes reversible multimerization phenomena maintaining its catalytic activity. However from 60% v/v ethanol/buffer, population of folded partially states with less catalytic activity are predominant.Access to document