AtGUS-E and AtGUS(-3t)-E were very similar with each other at some enzymatic properties, such as optimal pH and optimal temperature. It was reported in previous studies that many modified enzymes maintained some original enzymatic properties even though some sequence has been modulated [10] . Furthermore, we could also speculate that the non-conservative sequence lied outside of the catalytic face of the TIM barrel domain which may not affect the catalytically active residues and the GL biotransformation mode.