With development of molecular biology and bioinformatics characterization, an increasing number of sequence data have been cloned and applied in the biotransformation industry. Bioinformatics characterization from the National Center for Biotechnology Information (NCBI) showed that most b-glucuronidases belong to the glycoside hydrolase family (GHF) 2, and all of them consist of sugar-binding, immunoglobulin-like b-sandwich, and TIM barrel domains (triosephosphate isomerase, TIM) [13, 14, 15] . The TIM barrel domain, which is one of the most common catalytic domains, is adopted by about 10% of the enzymes; thus, sequence modification inside or outside the domain to improve the enzymatic property and determine the catalytic mechanism was reported in many studies. The site-directed mutagenesis of seven amino acids (aa) in the TIM barrel domain was performed to investigate the importance of the residue in the catalysis of an exo-b-d-glucosaminidase from Trichodema reesei [16] . Heparanase is an endo-b-d-glucuronidase, and its C-terminal region, which is not an integral part of the TIM barrel domain, is essential for the enzymatic activity and secretion of heparanase [17] .