High-yield enzymatic bioconversion of hydroquinone to α-arbutin, a powerful skin lightening agent, by amylosucrase.
α-Arbutin (α-Ab) is a powerful skin whitening agent that blocks epidermal melanin biosynthesis by inhibiting the enzymatic oxidation of tyrosine and L-3,4-dihydroxyphenylalanine (L-DOPA). α-Ab was effectively synthesized from hydroquinone (HQ) by enzymatic biotransformation using amylosucrase (ASase). The ASase gene from Deinococcus geothermalis (DGAS) was expressed and efficiently purified from Escherichia coli using a constitutive expression system. The expressed DGAS was functional and performed a glycosyltransferase reaction using sucrose as a donor and HQ as an acceptor. The presence of a single HQ bioconversion product was confirmed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The HQ bioconversion product was isolated by silica gel open column chromatography and its chemical structure determined by 1H and 13C nuclear magnetic resonance (NMR). The product was determined to be hydroquinone-O-α-D-glucopyranoside with a glucose molecule linked to HQ through an α-glycosidic bond. However, the production yield of the transfer reaction was significantly low (1.3%) due to the instability of HQ in the reaction mixture. The instability of HQ was considerably improved by antioxidant agents, particularly ascorbic acid, implying that HQ is labile to oxidation. A maximum yield of HQ transfer product of 90% was obtained at a 10:1 molar ratio of donor (sucrose) and acceptor (HQ) molecules in the presence of 0.2 mM ascorbic acid.
Graduate School of Biotechnology and Institute of Life Science and Resources, Kyung Hee University, Yongin, Korea.
Dong-Ho
DH
Seo
Jong-Hyun
JH
Jung
Suk-Jin
SJ
Ha
Hyun-Kug
HK
Cho
Dong-Hyun
DH
Jung
Tae-Jip
TJ
Kim
Nam-In
NI
Baek
Sang-Ho
SH
Yoo
Cheon-Seok
CS
Park
D001104:Arbutin / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D003001:Cloning, Molecular; D034301:Deinococcus / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli; D015870:Gene Expression; D005964:Glucosyltransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006873:Hydroquinones / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
D006873:Hydroquinones; D011994:Recombinant Proteins; D013395:Sucrose; D001104:Arbutin; D005964:Glucosyltransferases; C019700:amylosucrase; C031927:hydroquinone