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Halogenases with Potential Applications for the Synthesis of Halogenated Pharmaceuticals
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Georgette Rebollar-Pérez, Cynthia Romero-Guido, Antonino Baez, Eduardo Torres
Vanadium haloperoxidases are halogenating enzymes that can be found in bacteria, fungi and macroalgae where they catalyze the oxidative halogenation of electron-rich organic substrates (Kaysser et al., 2012). They were first found in the brown alga Ascophyllum nodosum (van Pée, 1996). Since the discovery of this first halogenase in marine kelp, vanadium bromoperoxidases (V-BPO) and vanadium CPOs have also been isolated (Butler and Sandy, 2009). These halogenases are enzymes that contain a vanadate (VO43−) moiety as prosthetic group and that catalyze the two-electron oxidation of halides (Cl–, Br–, I–). Unlike the heme-dependent haloperoxidases, these enzymes do not suffer from oxidative inactivation, which makes them more attractive from an operational point of view. Initially, hydrogen peroxide reacts at the distal position of the vanadate complex, producing a peroxo-vanadate intermediate. Then, halide ion is oxidized, which leads to the production of hypohalous acid as halogenating agent (Fig. 16.1b). Like the heme-dependent haloperoxidases, the vanadium-dependent enzymes catalyze the halogenation of a variety of substrates in a nonselective manner, resulting in several monohalogenated, dihalogenated and trihalogenated metabolites that are susceptible to electrophilic attack (Gkotsi et al., 2018).
Inorganic Nanoparticles as Enzyme Mimics
Published in Grunwald Peter, Biocatalysis and Nanotechnology, 2017
Ruben Ragg, Karsten Korschelt, Karoline Herget, Filipe Natalio, Muhammad Nawaz Tahir, Wolfgang Tremel
Haloperoxidases represent a class of enzymes with the capability of catalyzing the oxidation of halides (Cl–, Br–, I–) using hydrogen peroxide (H2O2) to form hypohalous acids. These acids can lead to the halogenation of suitable nucleophilic acceptors (Fig. 15.4) (Wever and Hemrika, 2006).
Mononuclear oxidodiperoxido vanadium(V) complex: synthesis, structure, VHPO mimicking oxidative bromination, and potential detection of hydrogen peroxide
Published in Journal of Coordination Chemistry, 2018
Haimanti Adhikari, Kalyan K. Mukherjea
Vanadium haloperoxidase (VHPO) is the first isolated vanadium-dependent enzyme from the marine algae Ascophyllum nodosum. In 1984 and later, it was found in some lichens and other marine algae as well [1, 2]. Vanadium-containing complexes have obtained attention due to their wide biological and catalytic properties such as haloperoxidation, nitrogen fixation, metalloprotein function, insulin-mimicking activities [3, 4]. The incorporation of halogen atoms in many organic compounds by nature leads to the formation of halogenated antibiotics, drugs, or signaling molecules in biological systems [5]. Halogenated compounds, usually found in marine organisms, especially marine macroalgae, seem to be important factors of halogen transfers in the coastal marine environment [6–8]. Among halogenating enzymes, haloperoxidases utilize hydrogen peroxide for electrophilic halogenation via the oxidation of halides [5, 9–12].
Is Cladophora fracta an efficient tool of accumulating critical raw materials from wastewater and there a potential health risk of use of algae as organic fertilizer?
Published in International Journal of Environmental Health Research, 2023
E. Işıl Arslan Topal, Erdal Öbek, Murat Topal
Since the measured concentrations of V in algae exposed to the wastewater significantly exceeded V concentration of the control, it is obvious that C. fracta efficiently accumulated V. It is known that V is required by algae. As reported in the literature, V haloperoxidases that are the enzymes that contain V are found in many algae (Almeida et al. 2001). Therefore, algae require V.