Journal of Food, Agriculture and Environment

Vol 9, Issue 3&4,2011
Online ISSN: 1459-0263
Print ISSN: 1459-0255

Variations in bioactivity and conformation of trypsin adsorbed on different size nanoparticles


Li Li, Hong-Hua Xu *, Yu-Jun Jiang, Guo-Ping Yu, Li-Gang Zhang, Yan Xu

Recieved Date: 2011-02-10, Accepted Date: 2011-10-06


The variations of conformation and enzyme activity of trypsin adsorbed on SiO2 particles of various sizes (20 nm, 100 nm, 300 nm and amorphous level) had been studied. The adsorption amount of trypsin clearly decreased with the increase of SiO2 particle sizes. The maximal adsorption amount was on 20 nm SiO2 at pH 7.8, and the relative activity of trypsin adsorbed on SiO2 of 20 nm, 100 nm, 300 nm and amorphous level at the same conditions was 61.3%, 56.3%, 43.5% and 23.2%, respectively. Both enzyme stability and protein structure were strongly dependent on the size of the particles. Smaller SiO2 particles enhanced trypsin stabilities in strongly denaturing environments to a greater extent than that of larger ones. When the SiO2-trypsin bioconjugates incubated at 80°C for 1h, the activity for trypsin adsorbed onto 20 nm, 100 nm, 300 nm and amorphous particles increased 96.3%, 70.8%, 45.7% and 19.7% of its native activity, respectively. The fraction of activity lost correlated well with the increase of surface hydrophobicity, and greater increase in surface hydrophobicity was observed for the trypsin adsorbed onto larger nanoparticles under otherwise similar conditions. DSC measurement also confirmed that the size of the nanoparticles influenced the attachment of protein structure and thermal stability.


Trypsin, SiO2 particles, adsorption, enzyme activity, surface hydrophobicity, DSC measurement

Journal: Journal of Food, Agriculture and Environment
Year: 2011
Volume: 9
Issue: 3&4
Category: Food and Health
Pages: 167-171

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