Structural-functional analyses of textile dye degrading azoreductase, laccase and peroxidase: a comparative in silico study

Background: Textile industry not only plays a vital role in our daily life but also a prominent factor in improving global economy. One of the environmental concern is it releases huge quantities of toxic dyes in the water leading to severe environmental pollution. Bacterial laccase and azoreductase successfully oxidize complex chemical structure of nitrogen group-containing azo dyes. Additionally, the presence of textile dye infuriates bacterial peroxidase to act as a dye degrading enzyme. Our present study deals with three textile dye degrading enzymes laccase, azoreductase, and peroxidase through analyzing their structural and functional properties using standard computational tools. Result: According to the comparative analysis of physicochemical characteristics, it was clear that laccase was mostly made up of basic amino acids whereas azoreductase and peroxidase both comprised of acidic amino acids. Higher aliphatic index ascertained the thermostability of all these three enzymes. Negative GRAVY value of the enzymes confirmed better water interaction of the enzymes. Instability index depicted that compared to laccase and preoxidase, azoreductase was more stable in nature. It was also observed that the three model proteins had more than 90% of total amino acids in the favored region of Ramachandran plot. Functional analysis revealed laccase as multicopper oxidase type enzyme and azoreductase as FMN dependent enzyme, while peroxidase consisted of α-ß barrel with additional haem group. Conclusion: Present study aims to provide knowledge on industrial dye degrading enzymes, choosing the suitable enzyme for industrial set up and to help in understanding the experimental laboratory requirements as well.

Establishment and Application of an Automated Chiral Two-dimensional High Performance Liquid Chromatography for Bio-analysis of D-Acidic Amino Acids / 分析化学

The physiological and bio-marker function of D-acidic amino acids is now becoming the hot topic on metabolomics study and new drug discovery. A fully automated two-dimensional high performance liquid chromatography (2D-HPLC) system was established by using monolithic ODS column as the first dimension column, acetonitrile-trifluoro acetic acid-water (9: 0. 05: 92, V/ V) as the mobile phase; micro Chiralpak QD-1-AX column as the enantiomer separation column, 10 mmol/ L citric acid in methanol-acetonitrile (50: 50, V/ V) as the mobile phase for the second dimension, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) as the fluorometrical derivative reagent. The separation efficiency ( Rs > 2. 5), determination sensitivity ( LOD =1 fmol) of acidic amino acids enantiomers were higher than those of existing methods, and an online confirmation of the enantiomers amounts was also achieved using this system. The recoveries were around 97-104% , RSD values for intra-day and inter-day precision were less than 5% for the acidic amino acids enantiomers in the biological samples. Furthermore, by analyzing the aging model senescence accelerated mouse prone 1 (SAMP1) mice which have low immunocompetence, the amounts of D-aspartic acid in thymus and spleen were determined as (206±18) and (264±21) nmol/ g, respectively. It is the first time that an obvious trend of the increasement of D-aspartic acid (p<0. 01) was observed in thymus and spleen of SAMP1 mice compare to senescence accelerated mouse resistant 1 (SAMR1) mice.