Search results for "REDUCTASE"

2015

Chemical ligation has been used to alter motions in specific regions of dihydrofolate reductase from E. coli and to investigate the effects of localized motional changes on enzyme catalysis. Two isotopic hybrids were prepared; one with the mobile N-terminal segment containing heavy isotopes (2H, 13C, 15N) and the remainder of the protein with natural isotopic abundance, and the other one with only the C-terminal segment isotopically labeled. Kinetic investigations indicated that isotopic substitution of the N-terminal segment affected only a physical step of catalysis, whereas the enzyme chemistry was affected by protein motions from the C-terminal segment. QM/MM studies support the idea th…

Cytochrome oxidase activity in the mitochondria of unfertilized and fertilized sea urchin eggs

1959

Abstract The cytochrome oxidase activity of isolated mitochondria of unfertilized and fertilized eggs of Paracentrotus lividus has been studied. It has been found that whereas in the mitochondria of unfertilized eggs saturation is reached at a cytochrome c concentration of 3.28 × 10−5 M, in those of fertilized eggs this occurs at a concentration of 5.74 × 10−5 M. It is shown that upon fertilization an increase of about 30 per cent of the activity of cytochrome oxidase takes place and no further changes appear to occur until blastula stage.

Cellular effects of HMG-CoA reductase inhibitors on blood cells (monocytes, macrophages, platelets)

2002

Atherosclerosis is the primary cause of ischaemic heart disease (IHD) and stroke and the leading cause of death and long-term disabilities in westernized societies. Several important environmental and genetic risk factors are associated with atherosclerosis. Over the past decade, it has become evident that atherosclerosis is not simply an inevitable degenerative consequence of ageing, but rather a chronic inflammatory condition connecting altered cholesterol metabolism and other risk factors to the development and progression of the atherosclerotic lesion and its sequelae like plaque rupture, fibrosis, calcification and thrombosis [1].

Lifestyle and impact on cardiovascular risk factor control in coronary patients across 27 countries: Results from the European Society of Cardiology …

2019

Aims The aim of this study was to determine whether the Joint European Societies guidelines on secondary cardiovascular prevention are followed in everyday practice. Design A cross-sectional ESC-EORP survey (EUROASPIRE V) at 131 centres in 81 regions in 27 countries. Methods Patients (<80 years old) with verified coronary artery events or interventions were interviewed and examined ≥6 months later. Results A total of 8261 patients (females 26%) were interviewed. Nineteen per cent smoked and 55% of them were persistent smokers, 38% were obese (body mass index ≥30 kg/m2), 59% were centrally obese (waist circumference: men ≥102 cm; women ≥88 cm) while 66% were physically active <30 min 5…

Effects of statins, fibrates, rosuvastatin, and ezetimibe beyond cholesterol: the modulation of LDL size and subclasses in high-risk patients.

2007

Increasing evidence suggests that the quality-rather than just the quantity-of low-density lipoproteins (LDLs) exerts a great influence on cardiovascular risk. LDLs comprise multiple subclasses with discrete size and density, and different physicochemical composition, metabolic behaviors, and atherogenicity. Individuals generally cluster into 2 broad subgroups. Most have a predominance of large LDLs, and some have a higher proportion of small particles. Small, dense LDLs are good predictors of cardiovascular events and progression of coronary artery disease. Their predominance has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Tre…

Treatment options for managing atherogenic dyslipidemia and fatty liver disease

2014

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in Western countries with up to 30% of the population affected. Since NAFLD is associated with an increased risk of cardiovascular (CV) disease, these patients should be stratified for CV risk factors, including atherogenic dyslipidemia, and managed accordingly. Lifestyle modifications represent an effective treatment for NAFLD, since most patients are overweight or obese. Also, promising, but not conclusive, results are available for current pharmacologic treatment. Drugs potentially effective against NAFLD include insulin sensitisers as well as fibrates and omega-3 polyunsaturated fatty acids, whil…

4-hydroxynonenal inhibits glutathione peroxidase: protection by glutathione

1999

Abstract 4-Hydroxy-2,3-trans-nonenal, a lipid peroxidation product, inhibits glutathione peroxidase in a concentration-dependent manner. The concentration providing 50% inhibition is 0.12 mM. This inhibition can be almost completely (89%) prevented by 1 mM glutathione added to the incubation mixture 30 min before 4-hydroxy-2,3-trans-nonenal or 2,3-trans-nonenal, but not by other thiol-containing antioxidants such as 0.5 mM dithiothreitol or β-mercaptoethanol. Again the addition of 1 mM glutathione, and not of 0.5 mM dithiothreitol or β-mercaptoethanol, to the enzyme 30 min after incubation with 4-hydroxy-2,3-trans-nonenal restores activity to the same extent as does the preincubation with G…

Cloning and expression of two novel aldo-keto reductases fromDigitalis purpurealeaves

2002

The aldo-keto reductase (AKR) superfamily comprises proteins that catalyse mainly the reduction of carbonyl groups or carbon–carbon double bonds of a wide variety of substrates including steroids. Such types of reactions have been proposed to occur in the biosynthetic pathway of the cardiac glycosides produced by Digitalis plants. Two cDNAs encoding leaf-specific AKR proteins (DpAR1 and DpAR2) were isolated from a D. purpurea cDNA library using the rat Δ4-3-ketosteroid 5β-reductase clone. Both cDNAs encode 315 amino acid proteins showing 98.4% identity. DpAR proteins present high identities (68–80%) with four Arabidopsis clones and a 67% identity with the aldose/aldehyde reductase from Medi…

The Structure and Metabolism of Carbohydrates

1994

Compared with the variety of carbohydrates in plants, relatively few sugars or sugar derivatives are regularly found in animals either free or as components of more complex compounds. However, it is possible that sugars originating from plants in the diet are transiently retained in animals and distort the normal sugar spectrum. Approximately a dozen sugars and sugar derivatives are regularly found in animals: the pentoses d-ribose and 2-deoxy-d-ribose; the hexoses d-glucose, d-galactose, d-mannose, d-fructose and l-fucose; the uronic acids d-glucuronic acid and l-iduronic acid; and the hexosamines d-glucosamine and d-galactosamine. In addition, d-erythrose, d-ribulose, d-xylulose and d-sed…

Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase.

2015

This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Δ(1)-pyrroline as degradation product from putrescine indicate that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine, and, to a lesser extent, polyamines, such as spermidine, but not monoamines. The kinetic constants (Km and Vmax) for the two major substrates were 94 ± 10 μM and 2.3 ± 0.1 μmol/min·mg for putrescine and 75 ± 5 μM and 0.15 ± 0.02 μmo…