title: Purification and characterization of a naringinase from Aspergillus aculeatus JMUdb058.
abstract: A naringinase from Aspergillus aculeatus JMUdb058 was purified, identified, and characterized. This naringinase had a molecular mass (MW) of 348 kDa and contained four subunits with MWs of 100, 95, 84, and 69 kDa. Mass spectrometric analysis revealed that the three larger subunits were β-D-glucosidases and that the smallest subunit was an α-L-rhamnosidase. The naringinase and its α-L-rhamnosidase and β-D-glucosidase subunits all had optimal activities at approximately pH 4 and 50 °C, and they were stable between pH 3 and 6 and below 50 °C. This naringinase was able to hydrolyze naringin, aesculin, and some other glycosides. The enzyme complex had a K(m) value of 0.11 mM and a k(cat)/K(m) ratio of 14,034 s(-1) mM(-1) for total naringinase. Its α-L-rhamnosidase and β-D-glucosidase subunits had K(m) values of 0.23 and 0.53 mM, respectively, and k(cat)/K(m) ratios of 14,146 and 7733 s(-1) mM(-1), respectively. These results provide in-depth insight into the structure of the naringinase complex and the hydrolyses of naringin and other glycosides.
authors.affiliation: College of Bioengineering, Jimei University, Xiamen, Fujian Province 361021, PR China.
authors.forename: YueLong
authors.initials: Y
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Ni
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: HuiNong
authors.initials: H
authors.lastname: Cai
authors.forename: LiJun
authors.initials: L
authors.lastname: Li
authors.forename: WenJin
authors.initials: W
authors.lastname: Su
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D044950:Flavanones / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D013058:Mass Spectrometry; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D044950:Flavanones; D009097:Multienzyme Complexes; C039827:naringinase; D001617:beta-Glucosidase; C005274:naringin