125572-77-2Relevant academic research and scientific papers
Chemoenzymatic synthesis of naturally occurring phenethyl (1→6)-β-D-gluco-pyranosides
Kawahara, Eiji,Nishiuchi, Miho,Fujii, Mikio,Kato, Keisuke,Ida, Yoshiteru,Akita, Hiroyuki
, p. 1461 - 1470 (2007/10/03)
Direct β-glucosidation between phenethyl alcohol and D-glucose (5) using the immobilized β-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave a phenethyl β-D-glucoside (1) in 34% yield. The coupling of the phenethyl O-β-D-glucopyranoside congener (8) and methylthio-2,3,4-tri-O-acetyl-β-D-xylopyranoside (9), 2,3,4-tri-O-acetyl- α-L-arabinopyranosyl bromide (11), and methylthio 2,3,4-tri-O-acetyl- α-L-rhamnopyranoside (13) afforded the coupled products (10, 12, and 14), respectively. Deprotection of the coupled products (10, 12, and 14) afforded the synthetic phenethyl O-β-D-xylopyranosy-(1→6)- β-D- glucopyranoside (2), phenethyl O-α-L-arabinopyranosy-(1→6)-β-D- glucopyranoside (3), and phenethyl O-α-L-rhamnopyranosy- (1→6)-β-D-glucopyranoside (4), respectively.
Substrate specificity of beta-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing.
Ma,Mizutani,Hiratake,Hayashi,Yagi,Watanabe,Sakata
, p. 2719 - 2729 (2007/10/03)
We synthesized nine kinds of diglycosides and a monoglycoside of 2-phenylethanol to investigate the substrate specificity of the purified beta-primeverosidase from fresh leaves of a tea cultivar (Camellia sinensis var. sinensis cv. Yabukita) in comparison with the apparent substrate specificity of the crude enzyme extract from tea leaves. The crude enzyme extract mainly showed beta-primeverosidase activity, although monoglycosidases activity was present to some extent. The purified beta-primeverosidase showed very narrow substrate specificity with respect to the glycon moiety, and especially prominent specificity for the beta-primeverosyl (6-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl) moiety. The enzymes hydrolyzed naturally occurring diglycosides such as beta-primeveroside, beta-vicianoside, beta-acuminoside, beta-gentiobioside and 6-O-alpha-L-arabinofuranosyl-beta-D-glucopyranoside, but were unable to hydrolyze synthetic unnatural diglycosides. The purified enzyme was inactive toward 2-phenylethyl beta-D-glucopyranoside. The enzyme hydrolyzed each of the diglycosides into the corresponding disaccharide and 2-phenylethanol. These results indicate the beta-primeverosidase, a diglycosidase, to be a key enzyme involved in aroma formation during the tea manufacturing process.
The Role of Diglycosides as Tea Aroma Precursors: Synthesis of Tea Diglycosides and Specificity of Glycosidases in Tea Leaves
Matsumura, Sachiko,Takahashi, Shunya,Nishikitani, Mariko,Kubota, Kikue,Kobayashi, Akio
, p. 2674 - 2678 (2007/10/03)
Two general synthetic routes were established in order to synthesize two diglycosides, primeverosides (1) and vicianosides (2), found in tea leaves. Procedure 1 is based on the Koenig-Knorr type of condensation of aglycon alcohols and 1-α-bromohexabenzoylprimeverose (6) and is suitable for the condensation of primary alcohols. Procedure 2 is to combine tribenzoyl-β-D-glucoside (8) and 1-α-bromotribenzoylxylose (4). The primeveroside of a tertiary alcohol was synthesized by this method which is also applicable to the synthesis of vicianosides. The hydrolysis rate of each of the 12 synthesized glycosides by a crude tea enzyme was evaluated, which suggest that the main glycosidase is primeverosidase and the enzyme mixture shows substrate specificity to both the carbohydrate and aglycon moieties.
