- Glucosyltransferase Capable of Catalyzing the Last Step in Neoandrographolide Biosynthesis
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ApUGT, a diterpene glycosyltransferase from Andrographis paniculata, could transfer a glucose to the C-19 hydroxyl moiety of andrograpanin to form neoandrographolide. This glycosyltransferase has a broad substrate scope, and it can glycosylate 26 natural and unnatural compounds of different structural types. This study provides a basis for exploring the glycosylation mechanism of ent-labdane-type diterpenes and plays an important role in diversifying the structures used in drug discovery.
- Li, Yuan,Lin, Hui-Xin,Wang, Jian,Yang, Jian,Lai, Chang-Jiang-Sheng,Wang, Xing,Ma, Bao-Wei,Tang, Jin-Fu,Li, Yong,Li, Xin-Lin,Guo, Juan,Gao, Wei,Huang, Lu-Qi
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supporting information
p. 5999 - 6002
(2018/10/20)
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- Development of Photoaffinity Probe for the Discovery of Steviol Glycosides Biosynthesis Pathway in Stevia rebuadiana and Rapid Substrate Screening
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Functional discovery and characterization of the target enzymes responsible for the biosynthesis pathway coded for the genes is ongoing, and the unknown functional diversity of this class of enzymes has been revealed by genome sequencing. Commonly, it is feasible in annotating of biosynthetic genes of prokaryotes due to the existence of gene clusters of secondary metabolites. However, in eukaryotes, the biosynthetic genes are not compactly clustered in the way of prokaryotes. Hence, it remains challenging to identify the biosynthetic pathways of newly discovered natural products in plants. Steviol glycosides are one class of natural sweeteners found in high abundance in the herb Stevia rebaudiana. Here, we applied the chemoproteomic strategy for the proteomic profiling of the biosynthetic enzymes of steviol glycosides in Stevia rebaudiana. We not only identified a steviol-catalyzing UDP-glycosyltransferase (UGT) UGT73E1 involved in steviol glycoside biosynthesis but also built up a probe-based platform for the screening of potential substrates of functional uncharacterized UGT rapidly. This approach would be a complementary tool in mining novel synthetic parts for assembling of synthetic biological systems for the biosynthesis of other complex natural products.
- Li, Weichao,Zhou, Yiqing,You, Wenjing,Yang, Mengquan,Ma, Yanrong,Wang, Mingli,Wang, Yong,Yuan, Shuguang,Xiao, Youli
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p. 1944 - 1949
(2018/06/11)
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- A complete specific cleavage of glucosyl and ester linkages of stevioside for preparing steviol with a β-galactosidase from Sulfolobus solfataricus
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β-Galactosidases from Sulfolobus solfataricus have been used to synthesize galactooligosaccharide and lactulose. In this work, a β-galactosidase from S. solfataricus with weak β-glucosidase activity but high lipase activity was employed as catalyst to assist hydrolysis of stevioside to obtain steviol, an important starting reagent of synthetic bioactive materials and the main metablite of stevioside in human digistion. The β-galactosidase presented a strict substrate specifity on converting stevioside to steviol in a stoichiometric yield. The β-galactosidase favors the cleavage of glycoside linkages prior to cleavage of glycosyl ester linkage. The hydrolysis is external diffusion controlled and hence has to bear low substrate concentration in regular process, but this can be solved with product removal or enzyme immobilization. The immobilization of the β-galactosidase onto cross-linked chitosan microspheres did not enhance the enzyme's thermal or pH stability but eliminated the external diffusion, and therefore speeded the hydrolysis in 3 folds. The relative reaction activity dropped only 1.75% after 6 runs of using the immobilized β-galactosidase.
- Chen, Jun-Ming,Xia, Yong-Mei,Wan, Hui-Da,Wang, Hai-Jun,Liu, Xiang
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p. 126 - 131
(2014/06/10)
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- Solubilization of steviolbioside and steviolmonoside with γ-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside
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1,4-α-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-β-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-β-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-β-glucosyl-steviol), respectively, both of which are poorly soluble in an acetate buffer. It was found that the solubilities of SM and SB in the buffer solution were remarkably increased in the presence of γ-cyclodextrin (γ-CD). SB was solubilized in the buffer solution with the aid of γ-CD, and the solution was subjected to 1,4-α-transglucosylation by using a cyclodextrin glucanotransferase-starch system to give a mixture of products which were glucosylated at the 13-O-glycosyl moiety. This mixture was acetylated, and the acetate was subjected to chemical β-glucosylation of 19-COOH followed by deacetylation to afford compounds which have superior sweetness to S. In the same way, derivatives with superior sweetness were selectively prepared from RU through SM.
- Ohtani,Aikawa,Fujisawa,Kasai,Tanaka,Yamasaki
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p. 3172 - 3174
(2007/10/02)
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- BIOTRANSFORMATION OF STEVIOL BY CULTURED CELLS OF EUCALYPTUS PERRINIANA AND COFFEE ARABICA
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A new biotransformation product, steviol 19-β-gentiobiosyl ester, together with steviol 19-β-glucopyranosyl ester and steriol-13-O-β-glucopyranosyl ester (rubusoside), was isolated from Eucalyptus perriniana jar fermentor culture following the administration of steviol.Only rubusoside was isolated as a biotransformation product of steviol from Coffea arabica cell suspension culture.Key Word Index: Eucalyptus perriniana; Myrtaceae; Coffee arabica: Rubiaceae; cell suspension culture; biotransformation; steviol; rubusoside; steviol 19-β-gentiobiosyl ester; glucosylation.
- Orihara, Yutaka,Saiki, Kenji,Furuya, Tsutomu
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p. 3989 - 3992
(2007/10/02)
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