Oxygen evolving complex

Oxygen evolving complex

The oxygen evolving complex, (OEC) also known as the water-splitting complex, is a water oxidizing enzyme involved in the photooxidation of water during the light reactions of photosynthesis. Based on a widely accepted theory from 1970 by Kok, the complex can exist in 5 states: S0 to S4. Photons trapped by photosystem II move the system from state S0 to S4. S4 is unstable and reacts with water to produce free oxygen. Currently the functional mechanism of the complex is not completely understood. Much of the known data have been collected from flash experiments, EPR, and X-ray spectroscopy. [Kok, B., B. Forbush, and M. McGloin. 1970. Cooperation of charges in photosynthetic O2 evolution. I. A linear four-step mechanism. Photochem. Photobiol. 11:467–475.]

The OEC appears to to have a metalloenzyme core containing both manganese and calcium, with the empirical formula for the inorganic core of Mn4Ca1OxCl1–2(HCO3)y. Other characteristics of it have been reviewed; see [ [http://mrw.interscience.wiley.com/emrw/9780470862100/eic/article/ia128/current/abstract Abstract : Manganese: The Oxygen-Evolving Complex & Models1 : Encyclopedia of Inorganic Chemistry : Wiley InterScience ] ]

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Oxygen-evolving complex — The Kok cycle Possible arrangement of the metalloenzyme core of the OEC. The metal …   Wikipedia

  • Oxygen evolution — is the process of generating molecular oxygen through chemical reaction. Mechanisms of oxygen evolution include the oxidation of water during oxygenic photosynthesis, electrolysis of water into oxygen and hydrogen, and electrocatalytic oxygen… …   Wikipedia

  • Oxygen — This article is about the chemical element and its most stable form, O2 or dioxygen. For other forms of this element, see Allotropes of oxygen. For other uses, see Oxygen (disambiguation). nitrogen ← oxygen → fluorine ↑ O ↓ …   Wikipedia

  • Oxo ligand — In coordination chemistry, an oxo ligand is an oxygen atom bound only to one or more metal centers. These ligands can exist as terminal or (most commonly) as bridging atom (Fig. 1). Oxo ligands stabilize high oxidation states of a metal.[1] Fig.… …   Wikipedia

  • Photosynthese — Bei den Landpflanzen findet Photosynthese in den Chloroplasten statt, hier in der Blattspreite des Laubmooses Plagiomnium affine. Photosynthese oder Fotosynthese (altgriechisch φῶς phōs „Licht“ und …   Deutsch Wikipedia

  • Cytochrome b559 — Cytochrome b559, alpha (gene psbE) and beta (gene psbF)subunits Structure of Photosystem II from Thermosynechococcus elongatus.[1] Identifiers …   Wikipedia

  • Photosystem II — is the first protein complex in Light Dependent Photosynthesis. It is located in the thylakoid membrane of plants, algae and cyanobacteria. The enzyme uses photons of light to energize electrons which are then transferred through a variety of… …   Wikipedia

  • Light-dependent reactions — of photosynthesis at the thylakoid membrane See also: Light independent reactions The light dependent reactions , or light reactions, are the first stage of photosynthesis, the process by which plants capture and store energy from sunlight. In… …   Wikipedia

  • Manganese — Not to be confused with Magnesium. This article is about the chemical element. For the ghost town, see Manganese, Minnesota. For the steamship, see SS Manganese. chromium ← manganese → iron ↑ Mn ↓ Tc …   Wikipedia

  • Photosynthesis — Composite image showing the global distribution of photosynthesis, including both oceanic phytoplankton and vegetation …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”