Production and properties of threonine aldolase immobilisates

Dichiral β-hydroxy-α-amino acids are a highly valuable class of compounds from which pharmaceutically active intermediates for the synthesis of e.g. β-sympathomimetic drugs can be obtained. In lieu of laborious multi-step “classical” organic synthesis, biocatalysis using threonine aldolases (TAs) opens up a way to synthesise β-hydroxy-α-amino acids in one step. Although enzyme kinetics, stereospecificity as well as substrate specificity were and are matters of investigation, there is a lack of investigations addressing enzyme stability, which is crucial if the reaction is thought to be transferred to an economical scale. methods to immobilise the l-low specificity threonine aldolase of Escherichia coli (l-TA) were studied. After extensive screening the entrapment of the enzyme into a porous network of orthosilicate appeared to be the most promising method.