Immobilized horse liver alcohol dehydrogenase as an on-line high-performance liquid chromatographic enzyme reactor for stereoselective synthesis.

Horse liver alcohol dehydrogenase (HLADH) has been non-covalently immobilized on an immobilized artificial membrane (IAM) high-performance liquid chromatography (HPLC) stationary phase. The resulting IAM-HLADH retained the reductive activity of native HLADH as well as the enzyme's enantioselectivity and enantiospecificity. HLADH was also immobilized in an IAM HPLC stationary phase prepacked in a 13 x 4.1 mm ID column to create an immobilized enzyme reactor (HLADH-IMER). The reactor was connected through a switching valve to a column containing a chiral stationary phase (CSP) based upon p-methylphenylcarbamate derivatized cellulose (Chiralcel OJR-CSP). The results from the combined HLADH-IMER/CSP and chromatographic system demonstrate that the enzyme retained its activity and stereoselectivity after immobilization in the column and that the substrate and products from the enzymatic reduction could be transferred to a second column for analytical or preparative separation. The combined HLADH-IMER/CSP system is a prototype for the preparative on-line use of cofactor-dependent enzymes in large-scale chiral syntheses.