Title: Lanthionine
CAS Registry Number: 922-55-4
CAS Name: S-[(2R)-2-Amino-2-carboxyethyl]-L-cysteine
Additional Names: 3,3¢-thiodi-L-alanine; L-lanthionine; [R-(R*,R*)]-bis(2-amino-2-carboxyethyl)sulfide
Molecular Formula: C6H12N2O4S
Molecular Weight: 208.24
Percent Composition: C 34.61%, H 5.81%, N 13.45%, O 30.73%, S 15.40%
Literature References: A rare amino acid found in proteins; sulfide analog of cystine. First isolated as artifacts of wool hydrolysates. Isoln: M. J. Horn et al., J. Biol. Chem. 138, 141 (1941); from chick embryo: N. H. Sloane, K. G. Untch, Biochemistry 5, 2658 (1966); from silkworm and Japanese oak moth: D. R. Rao et al., ibid. 6, 1208. Synthesis: V. du Vigneaud, G. B. Brown, J. Biol. Chem. 138, 151 (1941). Structure studies: I. W. Stapleton, O. A. Weber, Int. J. Pept. Protein Res. 3, 243 (1971). Crystal structure: G. R. Desiraju, D. R. Rao, Acta Crystallogr. C46, 627 (1990).
Properties: Elongated hexagonal plates. mp 295-296° (dec). [a]D25 +9.4° (c = 1.4 in 2.4N NaOH); [a]D22 +8.6° (c = 5 in 2.4N NaOH); [a]D22 +6.0° (c = 1 in 1N NaOH).
Melting point: mp 295-296° (dec)
Optical Rotation: [a]D25 +9.4° (c = 1.4 in 2.4N NaOH); [a]D22 +8.6° (c = 5 in 2.4N NaOH); [a]D22 +6.0° (c = 1 in 1N NaOH)
Derivative Type: meso-Form
Properties: Six-sided plates having a triangular appearance from dil NH3. Softens at 270°, dec 304°. Stable to alkalies. Sol in dil acids and alkalies. Sparingly sol in water. Insol in alcohol, ether, chloroform, acetone.
Derivative Type: DL-Form
Properties: Elongated hexagonal plates. Chars at 240°, dec 286-292°.
Derivative Type: D-Form
Properties: Elongated hexagonal plates. Darkens at 245°, dec 293-295°. [a]D21 -8.0° (c = 5 in 2.4N NaOH).
Optical Rotation: [a]D21 -8.0° (c = 5 in 2.4N NaOH)
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