title: Hydrolysis of soy isoflavone glycosides by recombinant beta-glucosidase from hyperthermophile Thermotoga maritima.
abstract: A recombinant Thermotoga maritima beta-glucosidase A (BglA) was purified to homogeneity for performing enzymatic hydrolysis of isoflavone glycosides from soy flour. The kinetic properties K(m), k(cat), and k(cat)/K(m) of BglA towards isoflavone glycosides, determined using high-performance liquid chromatography, confirmed the higher efficiency of BglA in hydrolyzing malonylglycosides than non-conjugated glycosides (daidzin and genistin). During hydrolysis of soy flour by BglA at 80 degrees C, the isoflavone glycosides (soluble form) were extracted from soy flour (solid state) into the solution (liquid state) in thermal condition and converted to their aglycones (insoluble form), which mostly existed in the pellet to be separated from BglA in the reaction solution. The enzymatic hydrolysis in one-step and two-step approaches yielded 0.38 and 0.35 mg genistein and daidzein per gram of soy flour, respectively. The optimum conditions for conversion of isoflavone aglycones were 100 U per gram of soy flour, substrate concentration 25% (w/v), and incubation time 3 h for 80 degrees C.
authors.affiliation: Nanjing Engineering and Technology Research Center for Microbiology, Jiangsu Key Laboratory for Biodiversity and Biotechnology, Nanjing Normal University, Nanjing, People's Republic of China. xueyemin@njnu.edu.cn
authors.forename: Yemin
authors.initials: Y
authors.lastname: Xue
authors.forename: Jinjin
authors.initials: J
authors.lastname: Yu
authors.forename: Xiangfei
authors.initials: X
authors.lastname: Song
mesh_terms: D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D006868:Hydrolysis; D007529:Isoflavones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D015394:Molecular Structure; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013025:Glycine max / Q000737:chemistry; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics; D013997:Time Factors; D001617:beta-Glucosidase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D006027:Glycosides; D007529:Isoflavones; D011994:Recombinant Proteins; D001617:beta-Glucosidase
references.citation: J Agric Food Chem. 2006 Oct 4;54(20):7495-502
references.pmid: 17002413
references.citation: Anal Biochem. 1976 May 7;72:248-54
references.pmid: 942051
references.citation: J Nutr Biochem. 2005 Apr;16(4):205-12
references.pmid: 15808324
references.citation: J Agric Food Chem. 2007 Mar 21;55(6):2407-12
references.pmid: 17311399
references.citation: Appl Microbiol Biotechnol. 2008 May;79(1):51-60
references.pmid: 18340445
references.citation: Am J Clin Nutr. 2000 Jun;71(6 Suppl):1705S-7S; discussion 1708S-9S
references.pmid: 10837323
references.citation: J Biol Chem. 2006 Oct 6;281(40):30251-9
references.pmid: 16891302
references.citation: J Nutr. 2000 Jul;130(7):1695-9
references.pmid: 10867038
references.citation: J Biotechnol. 2000 Feb 17;77(2-3):275-86
references.pmid: 10682286
references.citation: Biotechnol Lett. 2004 Oct;26(19):1511-5
references.pmid: 15604789
references.citation: J Nutr. 1995 Sep;125(9):2307-15
references.pmid: 7666247
references.citation: Nutr Rev. 2003 Oct;61(10):346-51
references.pmid: 14604267
references.citation: Adv Exp Med Biol. 2004;546:121-65
references.pmid: 15584372
references.citation: J Agric Food Chem. 2003 Apr 9;51(8):2212-5
references.pmid: 12670158
references.citation: Am J Clin Nutr. 2002 Aug;76(2):447-53
references.pmid: 12145021
references.citation: J Nutr. 2005 May;135(5):1243-7
references.pmid: 15867312
references.citation: Appl Microbiol Biotechnol. 2006 Nov;73(2):314-20
references.pmid: 16715232