(S)-ketoprofen ethyl ester에 대해 높은 광학활성이 있는 Pseudomonas fluorescens KCTC 1767 유례 esterase의 PCR-Cloning과 정제

The comparative study of enzymes that catalyze a similar reactions but have different substrate spectrum and/or stereospecificity is a powerful approach to understanding the reaction mechanism between the relative enzymes, and it was also an useful tool to cloning the related enzyme, without the typical cloning from DNA library of genomic pools. For this purpose, we conducted an approach that the comparison at the molecular and protein level of esterases, from various sources including a previously identified (S)-stereospecific esterase of Pseudomonas sp. ES1. As expected, we found an esterase family genes that shared a high similarity at the protein and genetic level in the identical genus Pseudomonad. The striking structural and biochemical identity strongly suggested the family genes to be an identical one. We, hence, aligned the family genes and designated a degenerated primer for PCR-cloning using six Pseudomonas strains as templates. As a result, a recombinant esterase from Pseudomonas fluorescens KCTC 1767 was cloned and high-level expressed with high selectivity to (R,S)-ketoprofen ethyl ester. The enzyme exhibited a high ester-hydrolyzing activity to (S)-ketoprofen but did not hydrolyzed the opposite stereoisomer. Further characteristics were discussed in our presentation.