Objective: To study the β-glucosidase gene (bgy1) from Lactobacillus brevis that was cloned and expressed in Escherichia coli BL21 (DE3) and then using it for the biotransformation of gypenoside XVII.
Results: The bgy1 gene consists of 2283 bp encoding 761 amino acids, with homology to the glycosyl hydrolase family-3 protein domain. The enzyme (Bgy1) hydrolyzed the glucose moieties at the C-3 position and the outer glucose moieties at the C-20 position of gypenoside XVII. Using 0.1 mg enzyme ml(-1) in 20 mM sodium phosphate buffer at 30 °C and pH 6.0, 1 mg gypenoside XVII ml(-1) was transformed into 0.58 mg compound K ml(-1) within 6 h, with a corresponding molar conversion yield of 89 %.
Conclusion: The recombinant Bgy1 is considered potentially useful for the practical preparation of compound K.
Keywords: Biotransformation; Compound K; Gypenoside XVII; β-Glucosidase.