562043-82-7Relevant articles and documents
Biosynthesis of 2-O-d-glucopyranosyl-l-ascorbic acid from maltose by an engineered cyclodextrin glycosyltransferase from Paenibacillus macerans
Liu, Long,Han, Ruizhi,Shin, Hyun-Dong,Li, Jianghua,Du, Guocheng,Chen, Jian
, p. 101 - 107 (2013)
In this work, the specificity of cyclodextrin glycosyltransferase (CGTase) of Paenibacillus macerans towards maltose was improved by the site-saturation engineering of lysine 47, and the enzymatic synthesis of 2-O-d-glucopyranosyl-l- ascorbic acid (AA-2G) with l-ascorbic acid and maltose as substrates was optimized. Compared to the AA-2G yield of the wild-type CGTase, that of the mutants K47F (lysine→phenylalanine), K47P (lysine→proline), and K47Y (lysine→tyrosine) was increased by 17.1%, 32.9%, and 21.1%, respectively. Under the optimal transformation conditions (pH 6.5, temperature 36 C, the mass ratio of l-ascorbic acid to maltose 1:1), the highest AA-2G titer by the K47P reached 1.12 g/L, which was 1.32-fold of that (0.85 g/L) obtained by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltose specificity of the mutants K47F, K47P, and K47Y. It was also found that compared to the wild-type CGTase, the three mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. As revealed by the interaction structure model of CGTase with substrate, the enhancement of maltose specificity may be due to the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. The obtained mutant CGTases, especially the K47P, has a great potential in the large-scale production of AA-2G with maltose as a cheap and soluble substrate.
Enhanced 2- O-α- d -Glucopyranosyl- l -ascorbic Acid Synthesis through Iterative Saturation Mutagenesis of Acceptor Subsite Residues in Bacillus stearothermophilus NO2 Cyclodextrin Glycosyltransferase
Tao, Xiumei,Wang, Tian,Su, Lingqia,Wu, Jing
, p. 9052 - 9060 (2018)
Low synthesis yields of the l-ascorbic acid (l-AA) derivative 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2G) limit its application in the food industry. In this work, the AA-2G synthesis yield of Bacillus stearothermophilus NO2 cyclodextrin glycosyltransferase (CGTase) was improved. Nine residues within 10 ? of the catalytic residue Glu253 displaying ≤30% conservation and located in the acceptor subsite were selected for iterative saturation mutagenesis. The best mutant, K228R/M230L, produced a higher AA-2G yield with maltodextrin as the glucosyl donor than that produced by its parent wild-type. The l-AA Km values of the mutant K228R/M230L decreased by 35%, whereas the kcat/Km increased by 2.69-fold. Kinetic analysis indicated that K228R/M230L displayed enhanced l-AA specificity. These results demonstrate that acceptor subsite residues play an important role in acceptor substrate specificity. Mutant K228R/M230L afforded the highest AA-2G concentration (211 g L-1, 624 mM) reported to date after optimization of the reaction conditions.
The Vitamin C Analogue 2-O-β-D-Glucopyranosyl-L-ascorbic Acid in Rhizomes, Stems and Leaves of Lycium barbarum
Amini-Rentsch, Lara,Andlauer, Wilfried,Bubloz, Carole,Marti, Roger,Micaux, Fabrice,Piantini, Umberto,Udrisard, Isabelle
, p. 828 - 830 (2020/12/01)
Awareness of health benefits of goji berries coming from their bioactive compounds, mostly antioxidants like ascorbic acid, has grown. Recently, an ascorbic acid analogue from goji berries, the 2-O-β-D-glucopyranosyl-l-ascorbic acid has been reported. In
Enhanced Synthesis of 2-O-α- d -Glucopyranosyl- l -ascorbic Acid from α-Cyclodextrin by a Highly Disproportionating CGTase
Gudiminchi, Rama Krishna,Towns, Andrew,Varalwar, Subhash,Nidetzky, Bernd
, p. 1606 - 1615 (2016/03/15)
2-O-α-d-Glucopyranosyl-l-ascorbic acid (AA-2G) is an industrially important derivative of vitamin C [l-ascorbic acid (l-AA)]. A useful synthetic route toward AA-2G is the selective glucosylation of l-AA by cyclodextrin glucanotransferase (CGTase). However, the cyclodextrin donor substrate is utilized rather inefficiently, because only one of its constituent glucosyl residues is coupled to the l-AA acceptor. A CGTase catalyzing disproportionation of the linear maltooligosaccharide chain formed in the initial coupling reaction might utilize a greater portion of the substrate for l-AA glucosylation and thus boost the AA-2G yield of cyclodextrin conversion. We present here a detailed characterization of the transfer reactions involved in the formation of AA-2G from α-cyclodextrin by a commercial CGTase preparation from Thermoanaerobacter sp. (Toruzyme 3.0L). We demonstrate that besides coupling, disproportionation constitutes a major route of glucosylation of l-AA by this enzyme. l-AA glucosides with oligoglucosyl chains between 1 and 12 units long were produced in the reaction. After chain-trimming hydrolysis with glucoamylase, however, AA-2G was recovered as the sole product of the enzymatic transglucosylation. The molar yield of AA-2G from cyclodextrin was 1.4, thus clearly exceeding the maximal yield of 1 for the coupling reaction. Using conditions optimized for transfer efficiency and productivity, we obtained AA-2G at the highest concentration (143 g/L, 424 mM) so far reported from an enzymatic glucosylation of l-AA. The synthetic yield was 30% based on l-AA (250 g/L, 1420 mM) offered in ≤4.6-fold molar excess over α-cyclodextrin.
