Title: Selenocysteine
CAS Registry Number: 10236-58-5
CAS Name: 3-Selenyl-L-alanine
Synonyms: selenium cysteine
Molecular Formula: C3H7NO2Se
Molecular Weight: 168.05
Percent Composition: C 21.44%, H 4.20%, N 8.33%, O 19.04%, Se 46.99%
Literature References: Naturally occurring amino acid found in the active site of certain prokaryotic and eukaryotic enzymes. Highly oxidizable making synthesis difficult. Easily prepared from its oxidized form
selenocystine. Prepn of
dl-selenocystine: A. Fredga,
Sven. Kem. Tidskr. 48, 160 (1936); E. P. Painter,
J. Chem. Soc. 69, 229 (1947); of
l-form: H. Tanaka, K. Soda,
Methods Enzymol. 143, 240 (1987). Reduction of selenocystine and separation of L-selenocysteine: J. N. Burnell
et al., J. Inorg. Biochem. 12, 343 (1980). Chemical properties: R. E. Huber, R. S. Criddle,
Arch. Biochem. Biophys. 122, 164 (1967). Determn by HPLC/MS: H. E. Ganther
et al., Methods Enzymol. 107, 582 (1984); colorimetric determn: N. Esaki, K. Soda,
ibid. 143, 148 (1987). Identification of Se as a component in protein: S.-H. Oh
et al., Biochemistry 13, 1825 (1974). Characterization of selenocysteine as the Se containing amino acid moiety in various enzymes: J. E. Cone
et al., Proc. Natl. Acad. Sci. USA 73, 2659 (1976); J. B. Jones
et al., Arch. Biochem. Biophys. 195, 255 (1979); presence in the catalytic site of mammalian glutathione peroxidase: J. W. Forstrom
et al., Biochemistry 17, 2639 (1978); J. J. Zabrowski
et al., Biochem. Biophys. Res. Commun. 84, 248 (1978). Metabolism in animals: H. Tanaka
et al., Curr. Top. Cell. Regul. 27, 487 (1985). Identification of selenocysteine-specific tRNA: W. C. Hawkes
et al., Biochim. Biophys. Acta 699, 183 (1982); W. Leinfelder
et al., Nature 331, 723 (1988).
Review: T. C. Stadtman,
FASEB J. 1, 375-379 (1987).
Properties: pK 5.2. Unstable to acid hydrolysis.
pKa: pK 5.2
