Biomaterial Database

Oxidation-reduction potentials and spectral properties of some cytochromes from Thiobacillus versutus (A2). 1984

W P Lu, and R K Poole, and D P Kelly

Cytochromes c-550 (acidic), c-550 (basic), c-551 and c-552.5 from Thiobacillus versutus have been highly purified and characterized. Their spectral properties at 77 K are described. Oxidation-reduction titrations of cytochromes c-550 (acidic) and c-550 (basic) showed them to exhibit Nernst values of n = 1, with single redox centres in the cytochromes, and to have midpoint redox potentials at pH 7.0 (Em,7) of 290 and 260 mV, respectively. Cytochrome c-551 contained two separately titratable redox components, each giving n = 1. The low potential centre (55% of titratable cytochrome) and the high potential centre (45%) had Em,7 values of -115 and +240 mV, respectively. Cytochrome c-552.5 also contained at least two redox centres. One (65% of titratable cytochrome) had n = 1 and Em,7 = 220 mV. The remaining 35% appeared to be a low potential component with an Em,7 possibly as low as -215 mV. the roles of these cytochromes in respiratory thiosulphate oxidation are discussed.

UI	MeSH Term	Description	Entries
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
D002248	Carbon Monoxide	Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)	Monoxide, Carbon
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
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
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry
D013855	Thiobacillus	A genus of gram-negative, rod-shaped bacteria that derives energy from the oxidation of one or more reduced sulfur compounds. Many former species have been reclassified to other classes of PROTEOBACTERIA.	Thiobacillus denitrificans,Thiobacillus thioparus