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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

PEGylation as an efficient tool to enhance cytochrome c thermostability: a kinetic and thermodynamic study

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Santos, Joao H. P. M. [1, 2] ; Carretero, Gustavo [3] ; Ventura, Sonia P. M. [2] ; Converti, Attilio [4] ; Rangel-Yagui, Carlota O. [1]
Total Authors: 5
[1] Univ Sao Paulo, Dept Biochem & Pharmaceut Technol, BR-05508000 Sao Paulo - Brazil
[2] Univ Aveiro, Dept Chem, CICECO Aveiro Inst Mat, P-3810193 Aveiro - Portugal
[3] Univ Sao Paulo, Inst Chem, Dept Biochem, BR-05508000 Sao Paulo - Brazil
[4] Genoa Univ, Pole Chem Engn, Dept Civil Chem & Environm Engn, Via Opera Pia 15, I-16145 Genoa - Italy
Total Affiliations: 4
Document type: Journal article
Source: JOURNAL OF MATERIALS CHEMISTRY B; v. 7, n. 28, p. 4432-4439, JUL 28 2019.
Web of Science Citations: 1

Cytochrome-c from equine heart was kinetically and thermodynamically investigated either in its native (Cyt-c) or PEGylated forms with different PEGylation degrees (Cyt-c-PEG-4 and Cyt-c-PEG-8). Maximum activities were observed at 80 degrees C, and the irreversible deactivation was well described by first-order kinetics. The results of activity at different temperatures were used to estimate the activation energy of the catalysed Cyt-c reaction (E{*} = 10.22 +/- 0.40, 7.51 +/- 0.06 and 8.87 +/- 0.29 kJ mol(-1) for Cyt-c, Cyt-c-PEG-4 and Cyt-c-PEG-8) and the standard enthalpy variation of enzyme unfolding ( = 33.82 +/- 4.92, 109.4 +/- 13.1 and 58.43 +/- 3.11 kJ mol(-1) for Cyt-c, Cyt-c-PEG-4 and Cyt-c-PEG-8, respectively). The results of residual activity tests allowed estimating the activation energy (E-d{*} = 50.51 +/- 1.71, 72.63 +/- 0.89 and 63.36 +/- 1.66 kJ mol(-1) for Cyt-c, Cyt-c-PEG-4 and Cyt-c-PEG-8), enthalpy (Delta H-double dagger), entropy (Delta S-double dagger) and Gibbs free energy (Delta G(double dagger)) of the enzyme irreversible denaturation. The higher enthalpic contributions of PEGylated conjugates and the increase in Delta G(double dagger), compared to the native protein, indorsed the protective role of PEGylation. Negative values of Delta S-double dagger suggested the occurrence of an aggregation phenomenon by increasing the temperature, which was confirmed by circular dichroism. The estimated thermodynamic parameters suggest that PEGylated Cyt-c forms have enhanced thermostability, which would be of great significance for industrial biosensing applications. (AU)

FAPESP's process: 16/22065-5 - N-terminal pegylation of proteins and purification by aqueous two-phase systems
Grantee:Carlota de Oliveira Rangel Yagui
Support type: Regular Research Grants