Immobilization of Lepidium draba peroxidase on a novel Zn-MOF nanostructure

摘要

In the present study, ultrasound irradiation was utilized to synthesize a novel zinc metal-organic framework (MOF). Scanning electron microscopic images, exhibited homogenous morphology with a nano-sized distribution of the Zn-MOF structure as also confirmed by X-ray diffraction patterns. Following, physical immobilization of Lepidium draba peroxidase (LDP) were optimized on the Zn-MOF in phosphate buffer (50 mM, pH 6.5), ratio amount of MOF/enzyme; 7/1 after shaking for 15 min at 25 degrees C, with high protein loading of 109.9 mg/g and immobilization yield of 93.3%. Immobilized enzyme (IE) exhibited more than 330% enhanced specific activity and also exhibited more than 150% specific affinity to its substrate (3,3',5,5'-tetramethylbenzidine) with respect to the free enzyme (FE). Optimum temperature of the IE was obtained at 20 degrees C while its was 25 degrees C for the FE, and thermostability of the IE augmented at temperature of 30 degrees C and 40 degrees C by the factors of 104 and 108% respectively. pH stability under neutral and basic condition and storage stability of the IE improved with respect to the FE as well as its structural stability (T-m; 73 degrees C for I-E vs. 63 degrees C for F-E). Furthermore, immobilization is accompanied with alteration on the enzyme structure as revealed by the intrinsic and extrinsic fluorescence spectra. (C) 2021 Elsevier B.V. All rights reserved.