Efficient expression of chondroitinase ABC I for specific disaccharides detection of chondroitin sulfate

Chondroitinase ABC I (ChSase ABC I) is a key enzyme of chondroitin sulfate (CS) degradation and widely used for CS detection in the medicine filed. However, the recombinant ChSase ABC I was weakly expressed in Escherichia coli because the forms of it were mostly inclusion bodies. In this study, a signal peptide (pelB) was used for the soluble form expression of ChSase ABC I in E. coli. Then the culture condition for ChSase ABC I expression was optimized through response surface methodology. Results revealed that the expression level of ChSase ABC I in a 7.5 L fermentor (29.03 mL^-1) was approximately 1.65-fold higher than that of the shake flask level (17.55 mL^-1). The enzymatic properties and kinetic constants of recombinant ChSase ABC I were also studied. Recombinant ChSase ABC I was also used to detect the specific disaccharides content of CS from different sources. This study not only eliminates the problem of the enzyme expressed as an inclusion body, but also solves the current problem of expensive ChSase ABC. In a word, it would be an ideal strategy for ChSase ABC high-efficiency expression and a great method to detect specific disaccharides of CS in biomedical field.