Protein disulphide isomerase-induced refolding of sonochemically prepared Ribon...

• Author(s): Fernandes, Margarida M. ; Silva, Raquel ; Ferreira, Helena ; Donelli, Ilaria ; Freddi, G. ; Paulo, Artur Cavaco
• Date: 2012
• Persistent ID: http://hdl.handle.net/1822/22630
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Protein disulphide isomerase; Ribonuclease A; Ultrasound; Microspheres; Activity recovery; Protein release; Protein folding
• Document Type: Article
• Language: English

Description

The present communication describes for the first time the development of Ribonuclease A (RNase A) microspheres using the sonochemical method followed by an enzymatic treatment with protein disulphide isomerase (PDI). Ultrasound application induced changes on the protein physicochemical and biological properties: the enzymatic activity of RNase A was decreased in 35% and the free thiol groups content was significantly increased, probably due to the breakage of protein disulphide bonds and assembly of RNase A monomers. The deconvolution of amide I band, from Fourier Transform Infrared Spectroscopy, showed that the secondary structure of RNase A was slightly changed after microspherization. The PDI application on microspheres promoted the recovery of RNase A biological activity and induced the release of active protein into solution in its native state. These results were promoted by different states of PDI active site: oxidized and reduced, respectively. The PDI aptitude to catalyze the refolding of a protein substrate in the form of spheres is here reported.