earticle

영어

ω-Transaminase can be applied to asymmetric synthesis of chiral amines and unnatural amino acids from ketone precusors. Even though the ω-transaminase shows excellent enzyme properties for chiral synthesis via kinetic resolution, the asymmetric synthesis suffers from various limitations such as low substrate reactivity, severe product inhibition and enzyme instability. Here, we explored how the substrate selectivity is controlled to determine optimal reaction conditions for the asymmetric synthesis. We examined how Michaelis constants and specificity constants were affected by pH and analyzed the effect of structural differences of substrates on the enzyme activity. Aided by the kinetic information, we found that binding between substrate and enzyme is a rate-determining step and the ionic and hydrophobic binding interactions are differently affected by the medium pH. This study suggests that the optimal reaction conditions could have different pH values depending on the substrate type. This work was supported by BK21 program from the Korean Ministry of Education and Seoul R&BD Program (NT080612, KU080657).