Search results for "Heme"

Are Heme-Dependent Enzymes Always Using a Redox Mechanism? A Theoretical Study of the Kemp Elimination Catalyzed by a Promiscuous Aldoxime Dehydratase

2020

The design of biocatalysts is a goal to improve the rate, selectivity and environmental friendship of chemical processes in biotechnology. In this regard, the use of computational techniques has provided valuable assistance in the design of enzymes with remarkable catalytic activity. In this paper, hybrid QM/MM simulations have allowed getting an insight into the mechanism of a promiscuous aldoxime dehydratase (OxdA) for the Kemp elimination. We first demonstrate that, based on the use of linear response approximation (LRA) methods, the lowest energy electronic state of the benzisoxazole placed in the active sit of OxdA corresponds to a singlet state, being the triplet and the quintet state…

Antioxidant and Antiinflammatory Properties of Heme Oxygenase-1 in Osteoarthritic Articular Cells

2012

Heme oxygenase-1 (HO-1) is induced in cells by various stimuli as a defense system against oxidative stress. It is known that reactive oxygen species (ROS) participates in the initiation and progression of osteoarthritis (OA) and several antioxidant systems may protect cartilage components. HO-1 induction or CO release from CORM-2 counteracts oxidative stress and protects against proinflammatory and catabolic effects of interleukin-1β in OA chondrocytes, osteoblasts, and synoviocytes as well as in OA osteochondral explants. Both approaches have been able to downregulate the production of mediators such as reactive oxygen species, nitric oxide, matrix metalloproteinases, prostaglandin E2, cy…

2015

The rationale of the study was two-fold: (i) develop a functional synthetic model of the Cytochrome c oxidase (CcO) active site, (ii) use it as a convenient tool to understand or predict the outcome of the reaction of CcO with ligands (physiologically relevant gases and other ligands). At physiological pH and potential, the model catalyzes the 4-electron reduction of oxygen. This model was immobilized on self-assembled-monolayer (SAM) modified electrode. During catalytic oxygen reduction, electron delivery through SAMs is rate limiting, similar to the situation in CcO. This model contains all three redox-active components in CcO's active site, which are required to minimize the production o…

Experimental evidence for proton motive force-dependent catalysis by the diheme-containing succinate:menaquinone oxidoreductase from the Gram-positiv…

2006

In Gram-positive bacteria and other prokaryotes containing succinate:menaquinone reductases, it has previously been shown that the succinate oxidase and succinate:menaquinone reductase activities are lost when the transmembrane electrochemical proton potential, Deltap, is abolished by the rupture of the bacteria or by the addition of a protonophore. It has been proposed that the endergonic reduction of menaquinone by succinate is driven by the electrochemical proton potential. Opposite sides of the cytoplasmic membrane were envisaged to be separately involved in the binding of protons upon the reduction of menaquinone and their release upon succinate oxidation, with the two reactions linked…

Summary of Discussion on the Theme: “Biochemical, Physiological, and Pathobiochemical Basis for Parenteral Nutrition”

1976

Volatility transmission in the CO<inf>2</inf> and energy markets

2009

The main consequence of the launch, in 2005, of the European Union Emission Trading Scheme (EU ETS) has been the establishment of a price for carbon emissions. Thus, major energy producers in Europe are now aware of the impact of their polluting activities. The interest in analysing the carbon markets from a financial point of view has exponentially increased since the launch of the EU ETS. However, no research articles have focused their attention on the volatility transmission between CO 2 and energy markets. The aim of this paper is to fill this gap in the literature. Specifically, our particular interest is to examine whether or not conditional volatility is transmitted across those mar…

Sensing of Oxygen by Bacteria

2009

PCARE and WASF3 regulate ciliary F-actin assembly that is required for the initiation of photoreceptor outer segment disk formation

2020

Significance The photoreceptor outer segments are primary cilia, modified for phototransduction by incorporation of stacked opsin-loaded membrane disks that are continuously regenerated. This process is disrupted in several types of inherited retinal dystrophy, but the driving force remained unclear. We show that C2orf71/PCARE (photoreceptor cilium actin regulator), associated with inherited retinal dystrophy subtype RP54, efficiently recruits the Arp2/3 complex activator WASF3 to the cilium. This activates an actin dynamics-driven expansion of the ciliary tip, resembling membrane evagination in lamellipodia formation. Colocalization of this actin dynamics module to the base of the outer se…

ENERGY FOR ROMANIA FROM RENEWABLE RESOURCES

2012

The European Union admits the fact that energy is essential, for the development of the European economy, but that it also constitutes a challenge, due to the impact on climate change. In Romania, as well as in all the countries of the European Union, which have chosen to promote renewable energy, governments have come up with support frameworks for investors in this field. In Romania’s case, the option for green schemes and compulsory quotas was selected, meaning that each energy producer, which produces renewable energy, receives a number of green certificates for each MW produced, depending on the technology it uses. The price of such a green certificate varies between 27 – 55 Euros. The…

Children’s Right to Play and Its Implementation: A Comparative, International Perspective

2021

The child's right to play is specifically addressed in the framework of the Convention on the Rights of the Child. The international recognition of this right is the central theme of this study. Through a documentary analysis of the reports of the States Parties to the Convention and the Concluding Observations of the Committee on the Rights of the Child, the study assesses the recognition of this right. The entry into force of General Comment 17 on the right of the child to rest, recreation, play, recreational activities, cultural life and the arts (art. 31) in 2013 should have marked a turning point in policies on children in the States Parties, but this did not occur. Policies cannot be …