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.

Analysis of lactate and malate dehydrogenase enzyme profiles of selected major carps of wetland of Calcutta.

The East Calcutta Wetland (ECW), a Ramsar site in India, acts as the only sink for both city sewages as well as effluents from the surrounding small- scale industries and is alarmingly polluted with heavy metals. The three best edible major carp species rohu (Labeo rohita,), catla (Catla catla,) and mrigala (Cirrhinus mrigala) were undertaken to monitor lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) by cellulose acetate electrophoresis (CAE) to assess the effects of pollutants, if any. Crude tissue extracts were prepared from brain, eye, heart, skeletal muscle and kidney tissue respectively from each type of fish. No differences were not found in MDH of catla from both sites for all tissues analyzed in this study. Rohu also showed similar mobility for all tissues except for heart tissue which was distinctly different in fishes from ECW site than that of its counterpart from non ECW site. On the other hand, MDH of two tissues of mrigala, eye and muscle respectively showed different migration patterns. LDH profiles for all tissues of three fish species from both the sites were consistently similar, only the expression levels of muscle LDH of mrigala and kidney LDH of rohu varied little.