Biomaterial Database

Light-induced turnover of chloroplast cytochrome b-559 in the presence of N-methylphenazonium methosulphate. 1975

P Horton, and W A Cramer

In the presence of 0.1-5 muM N-methylphenazonium methosulphate approx. 50-70% oxidation of cytochrome b-559 can be induced by far-red light. The oxidation is best observed with long wavelength far-red light (732 nm) of moderate intensities (approx. 10(4) ergs/cm2 per s) and is reversed by subsequent illumination with red light. Concentrations of N-methylphenazonium methosulphate above 5 muM are inhibitory probably due to cyclic electron flow. The far-red oxidation is inhibited by low concentrations of the plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, while 3-(3,4-dichlorophenyl)-1,1-dimethylurea inhibits red light reduction and increases the amplitude of far-red oxidation. The effect of N-methylphenazonium methosulphate is mimicked by N-methyl-phenazonium ethosulphate, but not by pyocyanine or diaminodurene. Low concentrations (2-3 muM) of N-methylphenazonium methosulphate also stimulate a 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone-inhibitable red light reduction of cytochrome f.

UI	MeSH Term	Description	Entries
D008773	Methylphenazonium Methosulfate	Used as an electron carrier in place of the flavine enzyme of Warburg in the hexosemonophosphate system and also in the preparation of SUCCINIC DEHYDROGENASE.	Phenazine Methosulfate,5-Methylphenazinium Methyl Sulfate,5 Methylphenazinium Methyl Sulfate,Methosulfate, Methylphenazonium,Methosulfate, Phenazine,Methyl Sulfate, 5-Methylphenazinium,Sulfate, 5-Methylphenazinium Methyl
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010619	Phenazines
D010655	Phenylenediamines	Aniline compounds that contain two amino groups. They are used as a precursor in the synthesis of HETEROCYCLIC COMPOUNDS and POLYMERS. p-Phenylenediamine is used in the manufacture of HAIR DYES and is an ALLERGEN.
D011710	Pyocyanine	Antibiotic pigment produced by Pseudomonas aeruginosa.	Pyocyanin
D002734	Chlorophyll	Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.	Phyllobilins,Chlorophyll 740
D002736	Chloroplasts	Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.	Chloroplast,Etioplasts,Etioplast
D003580	Cytochromes	Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.	Cytochrome
D003991	Dibromothymoquinone	At low concentrations, this compound inhibits reduction of conventional hydrophilic electron acceptors, probably acting as a plastoquinone antagonist. At higher concentrations, it acts as an electron acceptor, intercepting electrons either before or at the site of its inhibitory activity.	2,5-Dibromo-3-methyl-6-isopropyl-p-benzoquinone,2,5 Dibromo 3 methyl 6 isopropyl p benzoquinone
D004237	Diuron	A pre-emergent herbicide.	DCMU,3-(3,4-Dichlorophenyl)-1,1-dimethylurea