title: Simultaneous synthesis of 2-phenylethanol and L-homophenylalanine using aromatic transaminase with yeast Ehrlich pathway.
abstract: 2-Phenylethanol is a widely used aroma compound with rose-like fragrance and L-homophenylalanine is a building block of angiotensin-converting enzyme (ACE) inhibitor. 2-phenylethanol and L-homophenylalanine were synthesized simultaneously with high yield from 2-oxo-4-phenylbutyric acid and L-phenylalanine, respectively. A recombinant Escherichia coli harboring a coupled reaction pathway comprising of aromatic transaminase, phenylpyruvate decarboxylase, carbonyl reductase, and glucose dehydrogenase (GDH) was constructed. In the coupled reaction pathway, the transaminase reaction was coupled with the Ehrlich pathway of yeast; (1) a phenylpyruvate decarboxylase (YDR380W) as the enzyme to generate the substrate for the carbonyl reductase from phenylpyruvate (i.e., byproduct of the transaminase reaction) and to shift the reaction equilibrium of the transaminase reaction, and (2) a carbonyl reductase (YGL157W) to produce the 2-phenylethanol. Selecting the right carbonyl reductase showing the highest activity on phenylacetaldehyde with narrow substrate specificity was the key to success of the constructing the coupling reaction. In addition, NADPH regeneration was achieved by incorporating the GDH from Bacillus subtilis in the coupled reaction pathway. Based on 40 mM of L-phenylalanine used, about 96% final product conversion yield of 2-phenylethanol was achieved using the recombinant E. coli.
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Joon-Young
authors.initials: JY
authors.lastname: Hwang
authors.forename: Jihyang
authors.initials: J
authors.lastname: Park
authors.forename: Joo-Hyun
authors.initials: JH
authors.lastname: Seo
authors.forename: Minho
authors.initials: M
authors.lastname: Cha
authors.forename: Byung-Kwan
authors.initials: BK
authors.lastname: Cho
authors.forename: Juhan
authors.initials: J
authors.lastname: Kim
authors.forename: Byung-Gee
authors.initials: BG
authors.lastname: Kim
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000613:Aminobutyrates / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D042843:Glucose 1-Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D010654:Phenylbutyrates / Q000378:metabolism; D010626:Phenylethyl Alcohol / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D000637:Transaminases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000613:Aminobutyrates; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D010654:Phenylbutyrates; D011994:Recombinant Proteins; D010649:Phenylalanine; C014328:2-amino-4-phenylbutyric acid; D000429:Alcohol Oxidoreductases; C019642:alcohol dehydrogenase (NADP+); D042843:Glucose 1-Dehydrogenase; D000637:Transaminases; D002262:Carboxy-Lyases; C109058:phenylpyruvate decarboxylase; D010626:Phenylethyl Alcohol