Biochemistry of selenium: a brief overview

Area of Science:

• Biochemistry
• Toxicology
• Biometals

Background:

• Selenium (Se) exhibits unique chemical properties in biological systems, differing significantly from sulfur.
• Selenols (R-SeH) are more acidic than mercaptans, existing primarily as anions (R-Se-) at physiological pH.
• This anionic form facilitates nucleophilic reactions, metal binding for detoxification, and acts as a leaving group.

Purpose of the Study:

• To elucidate the chemical behavior and biological roles of selenium.
• To understand selenium's interaction with metals and its detoxification mechanisms.
• To explore selenium metabolism and its incorporation into proteins.

Main Methods:

• Chemical property analysis of selenium compounds.
• Investigation of metal-selenium interactions.
• Study of in vivo selenium metabolism and methylation pathways.
• Identification of selenium-containing proteins.

Main Results:

• Selenium compounds readily bind metals, forming the basis for heavy metal detoxification.
• Metal ions like Hg, Cd, Pb, and Cu can effectively strip selenium from organoselenium compounds.
• Methylation of selenium compounds is a major detoxification pathway in animals, with highest activity in liver and kidney.
• Selenium is incorporated into proteins post-transcriptionally, with several Se-dependent proteins identified.

Conclusions:

• Selenium's unique chemistry, particularly the anionic selenol form, underpins its biological functions.
• Selenium plays a vital role in detoxification and is essential for the function of various proteins.
• Understanding selenium metabolism is crucial for its biological and toxicological implications.