Curcuminoids from rhizomes of Curcuma longa possess various biological activities. However, low aqueous solubility and consequent poor bioavailability of curcuminoids are major limitations to their use. In this study, curcuminoids extracted from turmeric powder using stevioside (Ste), rebaudioside A (RebA), or steviol glucosides (SG) were solubilized in water. The optimum extraction condition by Ste, RebA, or SG resulted in 11.3, 9.7, or 6.7mg/ml water soluble curcuminoids. Curcuminoids solubilized in water showed 80% stability at pH from 6.0 to 10.0 after 1week of storage at 25°C. The particle sizes of curcuminoids prepared with Ste, RebA, and SG were 110.8, 95.7, and 32.7nm, respectively. The water soluble turmeric extracts prepared with Ste, RebA, and SG showed the 2,2-diphenyl-1-picrylhydrazyl radical scavenging (SC50) activities of 127.6, 105.4, and 109.8μg/ml, and the inhibition activities (IC50) against NS2B-NS3(pro) from dengue virus type IV of 14.1, 24.0 and 15.3μg/ml, respectively.
An ammonium sulfate precipitation of fermentation broth produced by Bacillus 16 subtilis FBL-1 resulted in 2.9-fold increase of specific protease activity. An eluted protein 17 Manuscript Click here to download Manuscript BBEN-D-17-00495R1.docx Click here to view linked References 2 fraction from the column chromatographies using DEAE-Cellulose and Sephadex G-75 had 18 94.2-and 94.9-fold higher specific protease activity, respectively. An SDS-PAGE revealed a 19 band of purified protease at approximately 37.6 kDa. Although purified protease showed the 20 highest activity at 45C and pH 9.0, the activity remained stable in temperature range from 21 30C to 50C and pH range from 7.0 to 9.0. Protease activity was activated by metal ions 22 such as Ca 2+ , Mg 2+ , Mn 2+ , Fe 2+ , Ca 2+ and K + , but 10 mM Fe 3+ significantly inhibited enzyme 23 activity (53%). Protease activity was inhibited by 2 mM EDTA as a metalloprotease inhibitor, 24 but it showed good stability against surfactants and organic solvents. The preferred substrates 25 for protease activity were found to be casein (100%) and soybean flour (71.6%).
Transthyretin (TTR) is an essential transporter of a thyroid hormone and a holo-retinol binding protein, found abundantly in human plasma and cerebrospinal fluid. In addition, this protein is infamous for its amyloidogenic propensity, causing various amyloidoses in humans, such as senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. It has been known for over two decades that decreased stability of the native tetrameric conformation of TTR is the main cause of these diseases. Yet, mechanistic details on the amyloidogenic transformation of TTR were not clear until recent multidisciplinary investigations on various structural states of TTR. In this review, we discuss recent advancements in the structural understanding of TTR misfolding and amyloidosis processes. Special emphasis has been laid on the observations of novel structural features in various amyloidogenic species of TTR. In addition, proteolysis-induced fragmentation of TTR, a recently proposed mechanism facilitating TTR amyloidosis, has been discussed in light of its structural consequences and relevance to acknowledge the amyloidogenicity of TTR.
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