A reductase is an enzyme characterized as catalyzing a reduction reaction, making it one of the most significant enzymes in intra and extracellular biosynthesis of metal nanoparticles in fungus.
Examples of reductase enzymes include 5a-Reductase, 5b-Reductase, Dihydrofolate reductase, HMG-CoA reductase, Methemoglobin reductase, Ribonucleotide reductase, Thioredoxin reductase, E.coli nitroductase, and Methylenetetrahydrofolate reductase.
Quinone reductases are a large family of enzymes, of which NQO1 and NQO2 are the most prominent features, that catalyze the reduction of quinones to hydroquinones. The FAD-containing homodimers share many similar properties, although the their interactions with pyridine nucleotide cofactors and inhibitors are vastly different.
The structure of each enzyme within the reductase family is unique to the others. The transmembrane respiratory nitrate reductase, for example, consists of an alpha, 1 beta and 2 gamm while it carries an Enzyme Commission (EC) number of 188.8.131.52 and a CAS number of 37256-45-4. Meanwhile, the coding region for the reductase mRNA is present in exons 2 through 20 while the mRNA for HMG CoA reductase can differ vastly due to heterogeneity in both the 3′ and 5′ untranslated regions.
Reductase Function and Mechanisms
Enzyme inhibitors of the HMGCoA reductase boast antifungal activity against some yeast species while they only show very low toxicity levels towards mammalian cells, including human cells. Either HMG1, which is responsible for 83% of the protein, or HMG2 genes can provide viability but the deletion of both genes is lethal.
If the HMGCoA reductase is overexpressed, it will grow a resistance to inhibitors while underexpression can bring an increased sensitivity. Both HMG1 and HMG2 reductase activity have been shown to regulate the growth of certain yeast strains, suggesting it can be used as a microbiological screen to identify inhibitors of the human enzyme .
Aldehyde reductase activity has also been found in the spruce budworm. When both NAD(P)H and the gland homogenate are present, aldehyde can be broken down to a fatty alcohol. N2O reductase, which is found in various denitrifiers is responsible for performing the last step of denitrification.
The reductase group of enzymes are found in mammals as well as humans, interacting with various drugs to increase, reduce, or even destruct proteins and cells. Roughyl 70% of mRNA molecules found at sites with a 25> bp region are initiated while the 5’ end of the human reductase gene is isolated and utilized to map RNA transcripts. In human fibroblasts, utilization spans a region of about 25 nucleotides.
Single nucleotide polymorphisms within NQO1 and NQO2 can reduce the levels of functional proteins within the human body. Due to the high levels of the enzymes, along with their protein–protein interactions relating to the p53 tumor suppressor, have seen them become molecular targets in cancer treatments. Furthermore, their ability to bioactivate with an array of antitumor drugs has been noted.
Meanwhile, the ferredoxin reductase expression, which is is two orders of magnitude higher in steroidogenic tissues, contains two homologous genes (FDX1 and FDX2) that provides the synthesis of iron–sulfur clusters while the interaction domain consists of residues 56–90.