Heterogeneity of the Type 3 copper in Japanese-lacquer-tree (Rhus vernicifera) laccase.
نویسندگان
چکیده
The two steps of the titration of the Japanese-lacquer-tree (Rhus vernicifera) laccase with N3- [Morpurgo, Rotilio, Finazzi-Agrò & Mondovi (1974) Biochim. Biophys. Acta 336, 324-328; LuBien, Winkler, Thamann, Scott, Co, Hodgson & Solomon (1981) J. Am. Chem. Soc. 103, 7014-7016] were shown to be two distinct reactions, each involving one different portion of the native enzyme molecules. The difference consists in the oxidation state of the Type 3 Cu, which is reduced in the portion with higher affinity for N3- and oxidized in the portion with lower affinity for N3-. The difference is eliminated by treatment with oxidizing (H2O2) or reducing agents, and a single N3- adduct is then formed. The e.p.r. spectra of the H2O2-treated enzyme and of its F- derivatives support this interpretation of the results. The similarity of the spectroscopic properties of the high-affinity N3- adduct to those of the N3- adducts of half-met-haemocyanins and half-met-tyrosinase is discussed.
منابع مشابه
Titrations with ferrocyanide of japanese-lacquer-tree (Rhus vernicifera) laccase and of the type 2 copper-depleted enzyme. Interrelation of the copper sites.
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...
متن کاملOptical properties of japanese-lacquer-tree (Rhus vernicifera) laccase depleted of type 2 copper(II). Involvement of type-2 copper(II) in the 330nm chromophore.
1. Spectroscopic and functional properties of Japanese-lacquer-tree (Rhus vernicifera) laccase were re-investigated, with special emphasis on the relationships between the different types of copper centres (Types 1, 2, and 3). 2. On removal of the Type 2 Cu(II), a decrease of absorbance occurred in the wavelength region above 650 nm (delta epsilon 750 = 300 M-1 . cm-1) and around 330 nm (delta...
متن کاملStability of Japanese-lacquer-tree (Rhus vernicifera) laccase to thermal and chemical denaturation: comparison with ascorbate oxidase.
The thermal denaturation of laccase from the Japanese lacquer tree (Rhus vernicifera) was studied by differential scanning calorimetry. The endotherms of holo-laccase, type 2-Cu-depleted laccase and apo-laccase were deconvoluted into two independent two-state transitions, providing evidence for a domain structure of the protein. The correlation of the two transitions with the bleaching of coppe...
متن کاملNucleotide sequence of a cDNA clone encoding an acidic laccase from sycamore maple (Acer pseudoplatanus L.).
Laccases (p-diphenol:O, oxidoreductase, EC 1.1 0.3.2) are m,embers of a highly conserved class of metalloenzymes, the ”blue” copper oxidases, which includes ascorbate oxidase and ceruloplasmin (Rydén and Hunt, 1993). First identified more than 100 years ago in extracts of sap from the Japanese lacquer tree (Rhus vernicifera), laccases have since been identified in fungi, insects, higher plants,...
متن کاملLaccase versus Laccase-Like Multi-Copper Oxidase: A Comparative Study of Similar Enzymes with Diverse Substrate Spectra
Laccases (EC 1.10.3.2) are multi-copper oxidases that catalyse the one-electron oxidation of a broad range of compounds including substituted phenols, arylamines and aromatic thiols to the corresponding radicals. Owing to their broad substrate range, copper-containing laccases are versatile biocatalysts, capable of oxidizing numerous natural and non-natural industry-relevant compounds, with wat...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Biochemical journal
دوره 207 3 شماره
صفحات -
تاریخ انتشار 1982