Biomaterial Database

Titrations with ferrocyanide of japanese-lacquer-tree (Rhus vernicifera) laccase and of the type 2 copper-depleted enzyme. Interrelation of the copper sites. 1980

L Morpurgo, and M T Graziani, and A Desideri, and G Rotilio

1. Redox titrations are reported of the metal centres in Japanese-lacquer-tree (Rhus vernicifera) laccase with ferrocyanide. 2. The redox potential of Type 1 Cu was found to increase with ferrocyanide concentration up to a limiting value similar to that for the Type 1 Cu in Type 2 Cu-depleted enzyme (which is independent of ferrocyanide concentration). 3. The redox potential of the two-electron acceptor (Type 3 Cu) is also independent of ferrocyanide concentration in Type 2 Cu-depleted enzyme and lower than values reported for the native enzyme. 4. The two-electron acceptor is present in the oxidized state in the Type 2 Cu-depleted enzyme, though the latter lacks the 330 nm absorption band. 5. The redox potential of Type 2 Cu also depends on ferrocyanide concentration, at least in the presence of azide. 6. The redox potentials are affected by freezing the solutions and/or addition of azide, the latter binding to Type 2 Cu with affinity dependent on the redox state of the two-electron acceptor.

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
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D010947	Plants, Toxic	Plants or plant parts which are harmful to man or other animals.	Plants, Poisonous,Plant, Poisonous,Plant, Toxic,Poisonous Plant,Poisonous Plants,Toxic Plant,Toxic Plants
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D005295	Ferrocyanides	Inorganic salts of the hypothetical acid ferrocyanic acid (H4Fe(CN)6).
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012251	Toxicodendron	A genus (formerly part of Rhus genus) of shrubs, vines, or trees that yields a highly allergenic oleoresin which causes a severe contact dermatitis (DERMATITIS, TOXICODENDRON). The most toxic species are Toxicodendron vernix (poison sumac), T. diversilobum (poison oak), and T. radicans (poison ivy). T. vernicifera yields a useful varnish from which certain enzymes (laccases) are obtained.	Ivy, Poison,Oak, Poison,Poison Ivy,Poison Oak,Poison Sumac,Sumac, Poison,Rhus toxicodendron,Ivies, Poison,Oaks, Poison,Poison Ivies,Poison Oaks,Poison Sumacs,Rhus toxicodendrons,Sumacs, Poison,Toxicodendrons,toxicodendron, Rhus
D012977	Sodium Nitrite	Nitrous acid sodium salt. Used in many industrial processes, in meat curing, coloring, and preserving, and as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES. It is used therapeutically as an antidote in cyanide poisoning. The compound is toxic and mutagenic and will react in vivo with secondary or tertiary amines thereby producing highly carcinogenic nitrosamines.	Nitrite, Sodium
D013053	Spectrophotometry	The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.