Dual function of the selenoprotein PHGPx during sperm maturation

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) changes its physical characteristics and biological functions during sperm maturation. PHGPx exists as a Soluble peroxidase in spermatids but persist s in mature spermatozoa as an enzymatically inactive, oxidatively cross-lin ked, insoluble protein. in the midpiece of mature spermatozoa, PHGPx protei n represents at least 50 percent of the capsule material that embeds the he lix of mitochondria. The role of PHGPx as a structural protein may explain the mechanical instability of the mitochondrial midpiece that is observed i n selenium deficiency.