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Purification and characterization of a ginsenoside Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239.

Chang KH, Jo MN, Kim KT, Paik HD - Int J Mol Sci (2012)

Bottom Line: In the specificity tests, the enzyme was found to be active against ginsenoside Rb(1), but showed very low levels of activity against Rb(2), Rc, Rd, Re, and Rg(1).The enzyme hydrolyzed the 20-C,β-(1→6)-glucoside of ginsenoside Rb(1) to generate ginsenoside Rd and Rg(3), and hydrolyzed 3-C,β-(1→2)-glucoside to generate F(2).The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.

View Article: PubMed Central - PubMed

Affiliation: Division of Animal Life Science, Konkuk University, Seoul 143-701, Korea; E-Mails: khchang80@cj.net (K.H.C); ulul55@naver.com (M.N.J.).

ABSTRACT
Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239 was studied to develop a bioconversion process for minor ginsenosides. The specific activity of the purified enzyme was 46.5 times greater than that of the crude enzyme. The molecular weight of the native enzyme was estimated to be approximately 123 kDa. The optimal pH of the purified enzyme was pH 4.0, and the enzyme proved highly stable over a pH range of 5.0-10.0. The optimal temperature was 70 °C, and the enzyme became unstable at temperatures above 60 °C. The enzyme was inhibited by Cu(2+), Mg(2+), Co(2+), and acetic acid (10 mM). In the specificity tests, the enzyme was found to be active against ginsenoside Rb(1), but showed very low levels of activity against Rb(2), Rc, Rd, Re, and Rg(1). The enzyme hydrolyzed the 20-C,β-(1→6)-glucoside of ginsenoside Rb(1) to generate ginsenoside Rd and Rg(3), and hydrolyzed 3-C,β-(1→2)-glucoside to generate F(2). The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.

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Time course of growth and β-glucosidase production from Aspergillus niger KCCM 11239. ■, dry cell weight (DCW); ▲, β-glucosidase activity (U/mL).
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f1-ijms-13-12140: Time course of growth and β-glucosidase production from Aspergillus niger KCCM 11239. ■, dry cell weight (DCW); ▲, β-glucosidase activity (U/mL).

Mentions: Changes in dry cell weight (DCW) and the β-glucosidase activity of A. niger KCCM 11239 on PDB medium at 30 °C were assessed under aerobic conditions. Figure 1 illustrates the relationship between β-glucosidase activity for the supernatant and cellular growth. As can be seen in Figure 1, the formation of extracellular β-glucosidase activity is growth-associated, ending when the stationary phase of growth is reached. A maximum β-glucosidase activity of cultivation medium was obtained after 16 days (specific activity, 9.9 U/mg). After that, the enzymatic activities were not changed during further culturing. Cultivation was, therefore, halted at 16 days. The culture supernatants were collected and employed as the source of enzyme purification.


Purification and characterization of a ginsenoside Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239.

Chang KH, Jo MN, Kim KT, Paik HD - Int J Mol Sci (2012)

Time course of growth and β-glucosidase production from Aspergillus niger KCCM 11239. ■, dry cell weight (DCW); ▲, β-glucosidase activity (U/mL).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472798&req=5

f1-ijms-13-12140: Time course of growth and β-glucosidase production from Aspergillus niger KCCM 11239. ■, dry cell weight (DCW); ▲, β-glucosidase activity (U/mL).
Mentions: Changes in dry cell weight (DCW) and the β-glucosidase activity of A. niger KCCM 11239 on PDB medium at 30 °C were assessed under aerobic conditions. Figure 1 illustrates the relationship between β-glucosidase activity for the supernatant and cellular growth. As can be seen in Figure 1, the formation of extracellular β-glucosidase activity is growth-associated, ending when the stationary phase of growth is reached. A maximum β-glucosidase activity of cultivation medium was obtained after 16 days (specific activity, 9.9 U/mg). After that, the enzymatic activities were not changed during further culturing. Cultivation was, therefore, halted at 16 days. The culture supernatants were collected and employed as the source of enzyme purification.

Bottom Line: In the specificity tests, the enzyme was found to be active against ginsenoside Rb(1), but showed very low levels of activity against Rb(2), Rc, Rd, Re, and Rg(1).The enzyme hydrolyzed the 20-C,β-(1→6)-glucoside of ginsenoside Rb(1) to generate ginsenoside Rd and Rg(3), and hydrolyzed 3-C,β-(1→2)-glucoside to generate F(2).The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.

View Article: PubMed Central - PubMed

Affiliation: Division of Animal Life Science, Konkuk University, Seoul 143-701, Korea; E-Mails: khchang80@cj.net (K.H.C); ulul55@naver.com (M.N.J.).

ABSTRACT
Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239 was studied to develop a bioconversion process for minor ginsenosides. The specific activity of the purified enzyme was 46.5 times greater than that of the crude enzyme. The molecular weight of the native enzyme was estimated to be approximately 123 kDa. The optimal pH of the purified enzyme was pH 4.0, and the enzyme proved highly stable over a pH range of 5.0-10.0. The optimal temperature was 70 °C, and the enzyme became unstable at temperatures above 60 °C. The enzyme was inhibited by Cu(2+), Mg(2+), Co(2+), and acetic acid (10 mM). In the specificity tests, the enzyme was found to be active against ginsenoside Rb(1), but showed very low levels of activity against Rb(2), Rc, Rd, Re, and Rg(1). The enzyme hydrolyzed the 20-C,β-(1→6)-glucoside of ginsenoside Rb(1) to generate ginsenoside Rd and Rg(3), and hydrolyzed 3-C,β-(1→2)-glucoside to generate F(2). The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.

Show MeSH
Related in: MedlinePlus