title: The 1H-NMR relaxation of Rhus laccase: assignment to different types of copper.
abstract: 1H-NMR relaxation measurements of Rhus laccase showed that a portion of the relaxivity was specifically abolished by less than stoichiometric EDTA. Another portion of relaxivity was removed by addition of N3(-) to the EDTA saturated enzyme. This treatment or selective removal of the Type 2 Cu left a large residual paramagnetic relaxivity (1700 M-1s-1) which was assigned to the Type 1 Cu. It is concluded that only a portion of the laccase relaxivity can be assigned to the Type 1 Cu and that this copper type does not behave homogeneously: the two fractions have different relaxivity, 5200 and less than or equal to 2400 M-1s-1 respectively.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003300:Copper / Q000302:isolation & purification*; D004492:Edetic Acid; D042845:Laccase; D009682:Magnetic Resonance Spectroscopy; D010088:Oxidoreductases / Q000302:isolation & purification*; D010940:Plant Proteins / Q000302:isolation & purification; D010947:Plants, Toxic; D012251:Toxicodendron / Q000201:enzymology*
chemical_list: D010940:Plant Proteins; D003300:Copper; D004492:Edetic Acid; D010088:Oxidoreductases; D042845:Laccase