摘要
Lipase from Antarctic krill,with a molecular weight of 71.27kDa,was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange(DEAE)and gel filtration columns(Sephacryl S-100),resulting in 5.2%recovery with a 22.4-fold purification ratio.The optimal pH and temperature for enzyme activity were 8.0 and 45℃,respectively.Purified lipase had Km and Vmax values of 3.27mmolL−1 and 2.4Umg−1,respectively,using p-nitrophenyl laurate as the substrate.Lipase activity was enhanced by adding Ca2+and Mg2+ions in the concentration ranges of 0–0.5mmolL−1 and 0–0.3mmolL−1,respectively,while the activity was inhibited by a further increase in these ion concentrations.Fe3+and Cu2+ions showed obvious inhibitory effects on enzyme activity,and the inhibition rates were 71.8%and 53.3%when the ion concentrations were 0.5mmolL−1.
Lipase from Antarctic krill, with a molecular weight of 71.27 kDa, was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange（DEAE） and gel filtration columns（Sephacryl S-100）, resulting in 5.2% recovery with a 22.4-fold purification ratio. The optimal pH and temperature for enzyme activity were 8.0 and 45℃, respectively. Purified lipase had Km and Vmax values of 3.27 mmol L-1 and 2.4 U mg-1, respectively, using p-nitrophenyl laurate as the substrate. Lipase activity was enhanced by adding Ca2+ and Mg2+ ions in the concentration ranges of 0–0.5 mmol L-1 and 0–0.3 mmol L-1, respectively, while the activity was inhibited by a further increase in these ion concentrations. Fe3+ and Cu2+ ions showed obvious inhibitory effects on enzyme activity, and the inhibition rates were 71.8% and 53.3% when the ion concentrations were 0.5 mmol L-1.
基金
supported by the Marine S&T Fund of Shandong Province for the Pilot National Laboratory for Marine Science and Technology (Qingdao) (Nos. 2018 SDKJ0304-4-2, 2018SDKJ0303-1)
the Central Public-Interest Scientific Institution Basal Research Fund, Chinese Academy of Fishery Sciences (Nos. 2017HY-XKQ01-01, 2016ZD0902, 2018GH10)
the Central Public-Interest Scientific Institution Basal Research Fund, YSFRI, CAFS (No. 20603022018025)
the Aoshan S&T Innovation Project from Qingdao National Laboratory for Marine Science and Technology (No. 2015ASKJ02-02-04)
the Antarctic Marine Biological Resources Development and Utilization Project from the Ministry of Agriculture and Rural Affairs, People’s Republic of China (2017)
the Financial Fund of the Ministry of Agriculture and Rural Affairs, People’s Republic of China (Nos. NFZX2018, FSTICE2019)
