Purification, characterization, and functional groups of an extracellular aflatoxin M1 ‐detoxifizyme from Bacillus pumilus E‐1‐1‐1

An extracellular aflatoxin-detoxifizyme (DAFE) from Bacillus pumilus E-1-1-1 was purified. The molecular mass of the enzyme assessed by SDS-PAGE was found to be approximately about 58  kDa. Lysine, tryptophan, and histidine residues were necessary and major functional groups to maintain enzyme activity, disulfide bonds were observed. AbstractThe experiment was conducted to purify high activity extracellular enzymes, which were produced by a strain that we previously screened was able to degrade aflatoxin effectively, and speculate the functional groups of the enzyme associated with degradation. An extracellular aflatoxin ‐detoxifizyme (DAFE) fromBacillus pumilus E ‐1‐1‐1 was purified through a process including ammonium sulfate precipitation, ultrafiltration, Sephadex chromatography, and ion exchange chromatography. The molecular mass of the enzyme assessed by SDS‐PAGE was found to be approximately 58 kDa. The optimum reaction temperature and pH for the purified enzyme were 45°C and pH 7, respectively. The enzyme showed temperature stability of up to 60°C. Ba2+, Ca2+ Na+, Mn2+, EDTA, and β‐mercaptoethanol showed inhibitory effects on the enzyme activity. Mg2+, Fe3+, Zn2+ and K+were the activators of enzymes. This enzyme was composed of at least 15 kinds of amino acids. Lysine, tryptophan, and histidine residues were necessary and major functional groups to maintain enzyme activity, disulfide bonds were observed, serine residues had little effect on the enzym...

Source: MicrobiologyOpen - July 8, 2019 Category: Microbiology Authors: Xue ‐Jiao Zhang, Jie Gao, Jun Han, Xiang‐Hong Wang, Ya‐Xin Sang Tags: ORIGINAL ARTICLE Source Type: research