Pyruvate kinase (PK) is an essential component of cellular metabolism, converting ADP and phosphoenolpyruvate (PEP) to pyruvate in the final step of glycolysis. Of the four unique isoforms of pyruvate kinase, R (PKR) is expressed exclusively in red blood cells and is a tetrameric enzyme that depends on fructose-1,6-bisphosphate (FBP) for activation. PKR deficiency leads to hemolysis of red blood cells resulting in anemia.
View Article and Find Full Text PDFThe pathophysiologic mechanism of sickle cell disease (SCD) involves polymerization of deoxygenated haemoglobin S (HbS), leading to red blood cell (RBC) sickling, decreased RBC deformability, microvascular obstruction, haemolysis, anaemia and downstream clinical complications. Pharmacological increase in the concentration of oxygenated HbS in RBCs has been shown to be a novel approach to inhibit HbS polymerization and reduce RBC sickling and haemolysis. We report that GBT021601, a small molecule that increases HbS-oxygen affinity, inhibits HbS polymerization and prevents RBC sickling in blood from patients with SCD.
View Article and Find Full Text PDFPseudomonas species are ubiquitous in nature and include numerous medically, agriculturally and technologically beneficial strains of which the interspecific interactions are of great interest for biotechnologies. Specifically, co-cultures containing have been used for bioremediation, biocontrol, aquaculture management and wastewater denitrification. Furthermore, the use of biofilms, in combination with consortia-based approaches, may offer advantages for these processes.
View Article and Find Full Text PDFA series of macrocyclic analogues were designed and synthesized based on the cocrystal structure of small molecule plasma kallikrein (pKal) inhibitor, , with the pKal protease domain. This led to the discovery of a potent macrocyclic pKal inhibitor , with an IC of 2 nM for one olefinic isomer and 42.3 nM for the other olefinic isomer.
View Article and Find Full Text PDFHomocysteinylation of lysine residues by homocysteine thiolactone (HCTL), a reactive homocysteine metabolite, results in protein aggregation and malfunction, and is a well-known risk factor for cardiovascular, autoimmune and neurological diseases. Human plasma paraoxonase-1 (PON1) and bleomycin hydrolase (Blmh) have been reported as the physiological HCTL detoxifying enzymes. However, the catalytic efficiency of HCTL hydrolysis by Blmh is low and not saturated at 20 mM HCTL.
View Article and Find Full Text PDFTienilic acid (TA) is selectively oxidized at the C-5 position of the thiophene ring by the human liver enzyme cytochrome P450 2C9 (CYP2C9). This oxidation is mediated by the proximal positioning of the thiophene over the heme iron, which is proposed to be coordinated by an interaction of the TA carboxylic acid to a cationic binding pocket in the enzyme active site. In this study, we investigated how chemical modification of TA influences the bioactivation by CYP2C9.
View Article and Find Full Text PDFThe mechanism by which acetaminophen (APAP) causes liver damage evokes many aspects drug metabolism, oxidative chemistry, and genetic-predisposition. In this study, we leverage the relative resistance of female C57BL/6 mice to APAP-induced liver damage (AILD) compared to male C57BL/6 mice in order to identify the cause(s) of sensitivity. Furthermore, we use mice that are either heterozygous (HZ) or null (KO) for glutamate cysteine ligase modifier subunit (Gclm), in order to titrate the toxicity relative to wild-type (WT) mice.
View Article and Find Full Text PDFAn NMR-based metabonomic approach was applied to study the systems level metabolic effects of two closely related thiophene compounds, tienilic acid (TA) and tienilic acid isomer (TAI). The metabonomic data were anchored with traditional clinical chemistry and histopathologic analyses. TA was removed from the market as a result of suspected immune-mediated hepatotoxicity, whereas TAI is an intrinsic hepatotoxin.
View Article and Find Full Text PDFThe uricosuric diuretic agent tienilic acid (TA) is a thiophene-containing compound that is metabolized by P450 2C9 to 5-OH-TA. A reactive metabolite of TA also forms a covalent adduct to P450 2C9 that inactivates the enzyme and initiates immune-mediated hepatic injury in humans, purportedly through a thiophene-S-oxide intermediate. The 3-thenoyl regioisomer of TA, tienilic acid isomer (TAI), is chemically very similar and is reported to be oxidized by P450 2C9 to a thiophene-S-oxide, yet it is not a mechanism-based inactivator (MBI) of P450 2C9 and is reported to be an intrinsic hepatotoxin in rats.
View Article and Find Full Text PDFFlutamide (FLU), a nonsteroidal antiandrogen drug widely used in the treatment of prostate cancer, has been associated with idiosyncratic hepatotoxicity in patients. It is proposed that bioactivation of FLU and subsequent binding of reactive metabolite(s) to cellular proteins play a causative role. A toxicogenomic study comparing FLU and its nitro to cyano analogue (CYA) showed that the nitroaromatic group of FLU enhanced cytotoxicity to hepatocytes, indicating that reduction of the nitroaromatic group may represent a potential route of FLU-induced hepatotoxicity [Coe et al.
View Article and Find Full Text PDFFlutamide (FLU) is an antiandrogen primarily used in the treatment of metastatic prostate cancer. It is an idiosyncratic hepatotoxicant that sometimes results in severe liver toxicity. FLU possesses a nitroaromatic group, which may be a contributor to its mechanism of toxicity.
View Article and Find Full Text PDFFine root distribution and turnover were investigated in ca. 40-year-old pure Norway spruce (Picea abies Karst.) stands in Germany, growing on four sites that differed in soil acidity (Ebergötzen < Barbis < Fichtelgebirge = Harz).
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