A hemoprotein, or heme protein, is a protein containing a heme prosthetic group, either covalently or noncovalently bound to the protein itself. The iron in the heme is capable of undergoing oxidation and reduction (usually to +2 and +3, though stabilized ferryl [Fe+4] compounds are well known in the peroxidases). Hemoproteins are found in such diverse roles as transport (hemoglobin, myoglobin, neuroglobin , cytoglobin and leghemoglobin), catalysis (peroxidases), active membrane transport (cytochromes), and electron transfer (cytochrome c).