Table 9. Different Types of Copper Proteins^a.

	mononuclear		dinuclear		tetranuclear
	type 1	type 2	type 3	CuA	CuZ
UV–vis spectrum	strong absorption, ∼600 nm and (in some proteins) 450 nm	weak absorption, ∼700 nm	300–400 nm	strong absorption, ∼480 and 530 nm	strong absorption, ∼640 nm
EPR spectrum	four-line (A|| < 80 × 10–4 cm–1)	four-line (A|| ≈ (130–180) × 10–4 cm–1)	nondetectable	seven-line (A|| ≈ 30–40 × 10–4 cm–1)	2 × four-line (A|| ≈ 61 × 10–4 cm–1 and A|| ≈ 24 × 10–4 cm–1)
common ligands	His, Cys (Met)	His, Asp (Tyr)	His (Tyr)	His, Cys (Met)	His, S2–
active site geometry	trigonal pyramidal or distorted tetrahedral	distorted tetragonal	tetragonal	trigonal planar	m4-S2– tetracopper cluster
examples	azurin	superoxide	hemocyanin	cyt c oxidase	N2O reductase
	plastocyanin	dismutase	tyrosinase	N2O reductase
	stellacyanin	galactose oxidase	catechol	menaquinol NO reductase
	nitrite reductase	amine oxidase	oxidase
		nitrite reductase	laccase
	laccase	laccase

^aReprinted with permission from ref (98). Copyright 2004 Elsevier.