Biotransformation of 2α,5α,10β,14β-tetra-acetoxy-4(20), 11-taxadiene by Ginkgo cell suspension cultures

Ginkgo biloba cell suspension cultures were used to biotransform 2α,5α,10β,14β-tetra-acetoxy-4(20),11-taxadiene. Two novel compounds were obtained and their structures were identified as 9α-hydroxyl-2α,5α,10β,14β-tetra-acetoxy-4(20), 11-taxadiene 1 and 9α, 10β-dihydroxyl-2α,5α,14β-tri-acetoxy-4(20), 11-taxadiene 2, respectively, on the basis of their physical and chemical data. Compound 1 was subsequently used as a substrate for the bioconversion by Ginkgo cell cultures, and the product obtained was confirmed to be the same as 2, which suggested that 2 is biosynthesized from 1. Investigation on properties of the related enzymes responsible for the biotransformation reaction through the experimental techniques of cell-free culture and substrate/product concentration analysis revealed that the enzymes were extracellular and constitutive.