Recombinant Fructosyl Peptide Oxidase from Eupenicellium terrenumand:
Periplasmic Secretion Could Improve the Solubility and activity of
Enzyme?
Abstract
HbA1c enzymatic method has been considered as a popular method for
determination of blood glucose. In this study, the methods for
decreasing the formation of Fructosyl Peptide Oxidase (FPOX) inclusion
bodies in E. coli and secretion of the enzyme into periplasmic space
using PelB signal peptide were investigated. Recombinant FPOX was mainly
expressed as inclusion bodies. The inclusion bodies of FPOX were only
soluble in urea 8 M, while was not soluble in any of used concentrations
of DMSO solvent. By freeze-thawing method, the inclusion bodies was
soluble in urea 8 M, but was not soluble in urea 0.5 M. By using the
stabilizers on solubility of rFPOX we found that the effect of sorbitol
was higher than arginine. The rFPOX was successfully secreted in the
periplasmic space using PelB signal peptide that shown the amount of
periplasmic protein in shuffle was higher than of BL21. For rFPOX
activity, TMB was used as coloring agent for the first time in HbA1c
enzymatic method as peroxidase substrate. In conclusion, FPOX inclusion
bodies are heterogenous in size and can be decreased using signal
peptide. The Freeze-thawing method can be used to solubilize FPOX
inclusion bodies at lower concentrations of urea.