Selenocysteine  is the 21st protein-building amino acid. It is almost the same as cysteine, but a selenium atom replaces the sulfur atom.
References[change | change source]
- ↑ abbreviated as Sec or U; and in older publications as Se-Cys
- ↑ Stadtman, Therese 1974. Selenium biochemistry. Science. 183 (4128): 915–22.  Archived 2016-12-22 at the Wayback Machine