37341-36-9Relevant academic research and scientific papers
The substrate specificity of a glucoamylase with steroidal saponin-rhamnosidase activity from Curvularia lunata
Feng, Bing,Kang, Li-ping,Ma, Bai-ping,Quan, Bo,Zhou, Wen-bin,Wang, Yong-ze,Zhao, Yu,Liu, Yi-xun,Wang, Sheng-qi
, p. 6796 - 6812 (2008/09/17)
In previous work, we studied and reported that an enzyme from Curvularia lunata 3.4381 had the novel specificity to hydrolyze the terminal rhamnosyl at C-3 position of steroidal saponin and obtained four transformed products; the enzyme was purified and ascertained as glucoamylase (EC 3.2.1.3 GA). In this work, the enzyme exhibiting steroidal saponin-rhamnosidase activity was systematically studied on 21?steroidal saponins and 6 ginsenosides. The results showed that the α-1,2-linked end-rhamnosyl residues at C-3 position of steroidal saponins could be hydrolyzed to corresponding secondary steroidal saponins, among which 18 compounds were isolated and identified, including 3 new secondary compounds. For the furostanosides having glucosyl residues at the C-26 position, hydrolysis occurred first at end-rhamnosyl at C-3 position to produce secondary furostanosides. The reaction of hydrolyzing glucosyl at C-26 position depended considerably on longer reaction times yielding the corresponding secondary spirostanosides (without rhamnosyl and glucosyl residues). The enzyme had the strict specificity for the terminal α-1,2-linked rhamnosyl residues of linear chain, or the terminal α-1,2-linked rhamnosyl residues with branched chain of 1,4-linked glycosyl residues of sugar chain at C-3 position of steroidal saponins, it was not specific for different aglycones, different glycons, and the number of glycon of sugar chain of steroidal saponin. The end-rhamnosyl of ginsenosides and p-nitrophenyl-α-l-rhamnopyranoside (pNPR) could not be hydrolyzed by the enzyme from C. lunata.
The microbiological transformation of steroidal saponins by Curvularia lunata
Feng, Bing,Ma, Bai-Ping,Kang, Li-Ping,Xiong, Cheng-Qi,Wang, Sheng-Qi
, p. 11758 - 11763 (2007/10/03)
The microbiological transformation of polyphyllin I (compound I), polyphyllin III (compound II), polyphyllin V (compound III) and polyphyllin VI (compound IV) by Curvularia lunata into their corresponding subsaponins, for example, diosgenin-3-O-α-l-arabinofuranosyl (1→4)-β-d- glucopyranoside (compound V), diosgenin-3-O-α-l-rhamnopyranosyl (1→4)-β-d-glucopyranoside (compound VI), diosgenin-3-O-β-d- glucopyranoside (compound VII) and pennogenin-3-O-β-d-glucopyranoside (compound VIII), were studied in this paper. Curvularia lunata is able to hydrolyze terminal rhamnosyls that are linked by 1→2 C- bond to sugar residues of steroidal saponins at C-3 position with high activity and regioselectivity.
