1.10.3.1 Ca2+ 124% activity at 10 mM 727570 1.10.3.1 Ca2+ highly activates PPO 701760 1.10.3.1 Co2+ 1 mM, slight stimulation 440427 1.10.3.1 copper - 686692 1.10.3.1 copper a copper-containing enzyme with a dinuclear copper centre 727570 1.10.3.1 copper contains copper 727645 1.10.3.1 copper the copper centers in the protein are directly involved in the catechol oxidation 657987 1.10.3.1 Cu+ 1 mM, 234% activity 440427 1.10.3.1 Cu2+ - 672547, 675076 1.10.3.1 Cu2+ 1 mM, 241% activity, enzyme contains 0.24% copper 440427 1.10.3.1 Cu2+ a copper enzyme 675166, 744954 1.10.3.1 Cu2+ a copper-containing enzyme 744952 1.10.3.1 Cu2+ a type 3 copper protein 726187 1.10.3.1 Cu2+ activates 713387 1.10.3.1 Cu2+ active site binding 671593 1.10.3.1 Cu2+ binuclear copper center each coordinated by three histidine nitrogen atoms, in the oxidized enzyme structure the 2 copper II centers contain a hydroxide bridging group completing the four-coordinated trigonal pyramidal coordination sphere, in the reduced form the CuI-CuI separation increases to 4.4 A and a water molecule coordinates to one copper 440439 1.10.3.1 Cu2+ bound to the enzyme, presently available for any tyrosinases, the central domain contains two copper binding sites, mettyrosinase, the resting form of tyrosinase, contains two tetragonal Cu(II) ions antiferromagnetically coupled through an endogenous bridge, although hydroxide exogenous ligands other than peroxide are bound to the copper site, the exogenous oxygen molecule is bound as peroxide and bridges the two copper centers 673001 1.10.3.1 Cu2+ bound to the enzyme, the central domain contains two copper binding sites, mettyrosinase, the resting form of tyrosinase, contains two tetragonal Cu(II) ions antiferromagnetically coupled through an endogenous bridge, although hydroxide exogenous ligands other than peroxide are bound to the copper site, the exogenous oxygen molecule is bound as peroxide and bridges the two copper centers 673001 1.10.3.1 Cu2+ copper enzyme 672593, 675458 1.10.3.1 Cu2+ copper-containing enzyme 672546, 674096, 674114, 674138, 711789 1.10.3.1 Cu2+ copper-containing metalloprotein 673560 1.10.3.1 Cu2+ the enzyme contains two copper ions (CuA and CuB) within the so-called coupled type 3 copper site, in the catalytic binuclear centre. The two copper ions in the catalytic centre of AoCO4 are each coordinated by the three histidine residues: His102 (a3), His110 (loop before a4) and His119 (a4) for CuA, and His284 (a8), His288 (a8) and His312 (a9) for CuB 725559 1.10.3.1 Cu2+ two Cu2+ ions per catalytic center 674774 1.10.3.1 Cu2+ type 3 copper enzyme, coordination number of 4 for each copper atom, CuII-CuII distance of 2.9 A 440435 1.10.3.1 Cu2+ when the concentration of PPO is about 66 mg/l, it shows its highest catalytic efficiency in the presence of 0.0001 mM Cu2+ 712878 1.10.3.1 Fe2+ activates 673783, 713387 1.10.3.1 H2O2 the exogenous oxygen molecule is bound as peroxide and bridges the two copper centers, conferring a distinct O2-Cu(II) charge transfer 673001 1.10.3.1 Hg2+ activates 713387 1.10.3.1 Mg2+ highly activates PPO 701760 1.10.3.1 Mg2+ stimulates activity to 112% at 10 mM 727570 1.10.3.1 Mn2+ activates 713387 1.10.3.1 Mn2+ highly activates PPO 701760 1.10.3.1 Mn2+ stimulates activity to 120% at 10 mM 727570 1.10.3.1 additional information artificial dinuclear copper complexes as functional models for catechol oxidase 440435 1.10.3.1 additional information Na+, K+, Cl- and SO42- have no effect on enzyme activity 727570 1.10.3.1 Ni2+ activates 713387 1.10.3.1 Pb2+ 1 mM, slight stimulation 440427 1.10.3.1 Zn2+ - 684704 1.10.3.1 Zn2+ 1 mM, slight stimulation 440427 1.10.3.1 Zn2+ 122% activity at 0.1 mM 727570 1.10.3.1 Zn2+ activates 673783