Chondroitinases (ChSases) are a family of polysaccharide lyases that can depolymerize high molecular weight chondroitin sulfate (CS) and dermatan sulfate (DS). In this study, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is stably expressed in different cells like normal cells and cancer cells and the expression is relatively insensitive to experimental conditions, was expressed as a fusion protein with ChSase ABC I. Results showed that the expression level and enzyme activity of GAPDH-ChSase ABC I were about 2.2 and 3.0 times higher than those of ChSase ABC I. By optimization of fermentation conditions, higher productivity of ChSase ABC I was achieved as 880 61 IU/g wet cell weight compared with the reported ones. The optimal temperature and pH of GAPDH-ChSase ABC I were 40 degrees C and 7.5, respectively. GAPDH-ChSase ABC I had a k(cat)/K-m of 131 +/- 4.1 L/mu mol s and the catalytic efficiency was decreased as compared to ChSase ABC I. The relative activity of GAPDH-ChSase ABC I remained 89% after being incubated at 30 degrees C for 180 min and the thermostability of ChSase ABC I was enhanced by GAPDH when it was incubated at 30, 35, 40 and 45 degrees C. (C) 2016 Elsevier Inc. All rights reserved.