Selenium and selenoproteins: an overview on different biological systems

Area of Science:

• Biochemistry
• Trace Element Metabolism
• Molecular Biology

Background:

• Selenium (Se) is an essential trace element crucial for life.
• Inorganic selenium exists in various oxidation states (selenate, selenite, elemental Se, selenide).
• Biological systems convert inorganic selenium into bioavailable organic forms, primarily selenocysteine and selenomethionine.

Purpose of the Study:

• To review strategies for selenium incorporation into proteins across different biological systems.
• To highlight the physiological importance of selenium.
• To discuss the implications of selenium deficiency.

Main Methods:

• Literature review focusing on selenium metabolism and selenoprotein synthesis.
• Analysis of biochemical pathways for selenium incorporation.
• Compilation of known selenoproteins in humans and microorganisms.

Main Results:

• Organisms convert inorganic selenium into selenocysteine and selenomethionine.
• Selenomethionine can replace methionine in proteins.
• "True" selenoproteins incorporate selenocysteine via a specific genetic code.
• Selenocysteine is vital for the catalytic activity of many enzymes.

Conclusions:

• Selenium incorporation into proteins is a fundamental biological process.
• Selenoproteins play critical roles in various physiological functions.
• Selenium deficiency can lead to health problems.