caa a22 4500 465822797 CHVBK 20180323112140.0 cr unu---uuuuu 170327e19901001xx s 000 0 eng 10.1007/BF00170916 doi (NATIONALLICENCE)springer-10.1007/BF00170916 Hummel Werner Forschungszentrum Jülich (KFA), Institut für Enzymtechnologie der Heinrich-Heine-Universität, PO Box 2050, D-5170, Jülich, Federal Republic of Germany aut Reduction of acetophenone to R (+)-phenylethanol by a new alcohol dehydrogenase from Lactobacillus kefir [Elektronische Daten] [Werner Hummel] Summary: A new alcohol dehydrogenase catalysing the enantioselective reduction of acetophenone to R(+)-phenylethanol was found in a strain of Lactobacillus kefir. A 70-fold enrichment of the enzyme with an overall yield of 76% was obtained in two steps. The addition of Mg2+ ions was found to be necessary to prevent rapid deactivation. The enzyme depends essentially on NADPH and was inactive when supplied with NADH as the coenzyme. Important enzymological data of the dehydrogenase are: K m (acetophenone) 0.6 mM, K m (NADPH) 0.14 mM, and a pH optimum for acetophenone reduction at 7.0. Addition of EDTA leads to complete deactivation of the enzyme activity. Added iodoacetamide or p-hydroxymercuribenzoate cause only slight inhibition, revealing that the active centre of the enzyme contains no essential SH-group. Besides acetophenone several other aromatic and long-chain aliphatic secondary ketones are substrates for this enzyme. Batch production of phenylethanol was examined using three different methods for the regeneration of NADPH: glucose/glucose dehydrogenase, glucose-6-phosphate/glucose-6-phosphate dehydrogenase, and isopropanol. Springer-Verlag, 1990 Applied Microbiology and Biotechnology Springer-Verlag 34/1(1990-10-01), 15-19 0175-7598 34:1<15 1990 34 253 https://doi.org/10.1007/BF00170916 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00170916 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Hummel Werner Forschungszentrum Jülich (KFA), Institut für Enzymtechnologie der Heinrich-Heine-Universität, PO Box 2050, D-5170, Jülich, Federal Republic of Germany aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer-Verlag 34/1(1990-10-01), 15-19 0175-7598 34:1<15 1990 34 253 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer