Two proteins, Mn2+, and low molecular cofactor are required for C-glucosyl-cleavage of mangiferin.
C-Glucosides, in which sugars are attached to the aglycone by carbon-carbon bonds, are generally resistant to acid and enzyme hydrolysis. The C-glucosyl bond of mangiferin, a xanthone C-glucoside, was cleaved by anaerobic incubation with a human intestinal bacterium, Bacteroides sp. MANG, to give norathyriol. A cell-free extract obtained by sonication of B. sp. MANG demonstrated cleaving activity for mangiferin to norathyriol by adding NADH, diaphorase, and dithiothreitol. Both high molecular weight (>10 k) and low molecular weight (<10 k) fractions obtained from the cell-free extract were required for the activity. MnCl2 was necessary for the activity, but other metal ions were not. By purification of the high molecular weight fraction using DEAE-cellulose and Phenyl Sepharose column chromatography, two fractions, designated as proteins A and B, were separated and required for the activity. Neither protein A nor protein B alone showed any activity. This is the first report describing a C-glucosyl-cleaving enzyme from human intestinal bacterium that seems to involve a novel enzyme mechanism.
Sanugul
Kanjana
K
Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
Akao
Teruaki
T
Nakamura
Norio
N
Hattori
Masao
M
D000693:Anaerobiosis; D001439:Bacteroides / Q000201:enzymology; D002474:Cell-Free System; D002712:Chlorides / Q000737:chemistry; D002848:Chromatography, DEAE-Cellulose; D002851:Chromatography, High Pressure Liquid; D003013:Clostridium / Q000201:enzymology; D004798:Enzymes / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D006868:Hydrolysis; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry; D008970:Molecular Weight; D014966:Xanthenes / Q000737:chemistry; D044004:Xanthones / Q000737:chemistry*
D002712:Chlorides; D004798:Enzymes; D017895:Manganese Compounds; D014966:Xanthenes; D044004:Xanthones; C013592:mangiferin; C069053:norathyriol; D008345:Manganese; D005947:Glucose; C025340:manganese chloride