Involvement of glutathione peroxidases in the occurrence and development of breast cancers

Table 1 The types of GPxs and their proven substrates

GPxs	Types	Expressions	Locations	Oxidizing substrates	Reducing substrate	Peroxidatic residue	References
GPx1	Selenium-dependent	Red cells, liver, lung, and kidney	Cytosol, nucleus, and mitochondria	H₂O₂, soluble low MM hydroperoxides	GSH	Sec	[17, 83]
GPx2	Selenium-dependent	Gastrointestinal tract	Cytosol and nucleus	N.F.	N.F.	Sec	[118,119,120]
GPx3	Selenium-dependent	Kidney, lung, epididymis, breast, heart, and muscle	Mitochondria	H₂O₂, soluble low MM hydroperoxides	GSH, low rate with thioredoxin and glutaredoxin	Sec	[17, 121]
GPx4	Selenium-dependent	Various tissues	Nucleus, cytosol, and mitochondria	H₂O₂, small hydroperoxides, hydroperoxides in complex lipids	GSH, Dithiothreitol	Sec	[122,123,124]
GPx5	Non-Selenium-dependent	Epididymis	Extracellular	N.F.	N.F.	Cys	[17, 125]
GPx6	Selenium-dependent in human	Olfactory epithelium	N.A.	N.F.	N.F.	Sec (human) Cys (rats)	[17, 126]
GPx7	Non-Selenium-dependent	Preadipocytes	N.A.	H₂O₂	GSH, Protein disulfide isomerase	Cys	[17, 127, 128]
GPx8	Non-Selenium-dependent	Lung	Endoplasmic reticulum	H₂O₂	GSH	Cys	[128, 129]

ISSN: 1479-5876