l-Ribose isomerase (lRI) is an enzyme that can catalyze the reversible isomerization between l-ribose and l-ribulose. It can also perform the conversion between many aldoses into their corresponding ketoses. l-RI was produced from Cryobacterium sp. N21 (CrL-RIse), and l-ribose was utilized as a substrate. The recombinant l-RI gene was cloned and overexpressed from Cryobacterium sp. N21. The purification of CrL-RIse was performed by metal-affinity chromatography. The enzyme displayed a corresponding band with an approximate size of 35 kDa on the SDS-PAGE analysis. The protein for this gene contains 266 amino acids with an expected molecular weight (Mw) of 29.6 kDa. The measured Mw of CrL-RIse calculated by HPLC was 125 kDa. CrL-RIse was extremely active in glycine buffer at 35 °C, pH 9.0, showing a specific activity of 54.96 U mg−1. CrL-RIse displayed no major increase in activity with metal ions, excluding Mn2+. The estimated Km, Kcat, Kcat/Km and Vmax values of CrL-RIse were 37.8 mM, 10,416 min−1, 275.43 min−1 mM−1, and 250 U mg−1, respectively. The rate of l-ribulose production was 31 % (6.24, 12.11, and 20.89 g L−1) at equilibrium by utilizing 20, 40, and 70 g L−1 of the substrate, respectively. The results indicated that CrL-RIse has the capability to manufacture l-ribulose from l-ribose. 相似文献
People with reduced esterase D (ESD) activity are susceptible to many diseases. However, how to activate ESD is still unknown. To address the question, we identified that 4-chloro-2-(5-phenyl-1-(pyridin-2-yl)-4, 5-dihydro-1H-pyrazol-3-yl) phenol (FPD5) could be a good candidate activator for ESD activity. We found that FPD5 could increase ESD activity in a dose-dependent way. FPD5 bound directly to ESD at Lys180 rather than its ubiquitination site Lys213. Site-directed mutagenesis at the binding site or the ubiquitination site inhibited FPD5 action. FPD5 increased the level of ESD mono-ubiquitination and mutESD K213A completely inhibited this action. Our findings highlighted the activation mechanism of ESD via promoting the mono-ubiquitination of ESD. 相似文献
The effects of two glycosylated whey hydrolysates (GWH-Gal A and GWH-Gal B) on glutathione (GSH) and related antioxidant enzymes in SGC-7901 cells were evaluated. Two whey glycosylated hydrolysates promoted an increase in reduced glutathione (GSH) in normal SGC-7901 cells. GSH, glutathione peroxidase (GPx), γ-glutamine cysteine synthetaase (γ-GCS), and catalase (CAT) at 1.0 and 2.0 mg/mL in normal SGC-7901 cells were higher in the GWH-Gal A group than in the GWH-Gal B group (P < 0.05). Compared with GWH-Gal B, GWH-Gal A more strongly inhibited decreases in intracellular GSH, GPx, γ-GCS, CAT, and superoxide dismutase (SOD) in H2O2-induced SGC-7901 cells. Compared with GWH-Gal B, GWH-Gal A at 1.0 and 2.0 mg/mL effectively inhibited increases in lactate dehydrogenase (LDH) and malondialdehyde (MDA) in H2O2-induced SGC-7901 cells (P < 0.05). Therefore, GSH content and related antioxidant enzyme activity levels (GPx, γ-GCS, CAT, SOD) in both normal and H2O2-induced SGC-7901 cells were considerably stronger in the GWH-Gal A group than in the GWH-Gal B group. 相似文献
A novel series of 3-hydroxyquinazoline-2,4(1H,3H)-diones derivatives has been designed and synthesized. Their biochemical characterization revealed that most of the compounds were effective inhibitors of HIV-1 RNase H activity at sub to low micromolar concentrations. Among them, II-4 was the most potent in enzymatic assays, showing an IC50 value of 0.41 ± 0.13 μM, almost five times lower than the IC50 obtained with β-thujaplicinol. In addition, II-4 was also effective in inhibiting HIV-1 IN strand transfer activity (IC50 = 0.85 ± 0.18 μM) but less potent than raltegravir (IC50 = 71 ± 14 nM). Despite its relatively low cytotoxicity, the efficiency of II-4 in cell culture was limited by its poor membrane permeability. Nevertheless, structure-activity relationships and molecular modeling studies confirmed the importance of tested 3-hydroxyquinazoline-2,4(1H,3H)-diones as useful leads for further optimization. 相似文献
Vegetable crops provide a rich source of essential nutrients for humanity and represent critical economic values to global rural societies. However, genetic studies of vegetable crops have lagged behind major food crops, such as rice, wheat and maize, thereby limiting the application of molecular breeding. In the past decades, genome sequencing technologies have been increasingly applied in genetic studies and breeding of vegetables. In this review, we recapitulate recent progress on reference genome construction, population genomics and the exploitation of multi-omics datasets in vegetable crops. These advances have enabled an in-depth understanding of their domestication and evolution, and facilitated the genetic dissection of numerous agronomic traits, which jointly expedites the exploitation of state-of-the-art biotechnologies in vegetable breeding. We further provide perspectives of further directions for vegetable genomics and indicate how the ever-increasing omics data could accelerate genetic, biological studies and breeding in vegetable crops.