Cysteic Acid


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Cysteic Acid

 

(also α-amino-β-sulfonylpropionic acid), HO3SCH(NH2)COOH; an amino acid containing sulfur. Cysteic acid is an intermediate in the metabolism of cysteine and cystine in animals. It participates in transamination reactions, and it is a precursor of taurine.

The oxidation of cysteine and cystine residues—components of peptides and proteins—yields cysteic acid. This oxidation reaction is used to determine the number and position of sulfhydryl groups (—SS) and disulfide groups (—S—S—) in various peptides and proteins. From this information, other information can be derived on the spatial structure of peptide chains and the arrangement of the chains in protein molecules.

References in periodicals archive ?
The final residue was redissolved in 250 uL of cysteic acid solution.
The disulfide bond S-S is oxidized to cysteic acid residues by hydrogen peroxide, and increasing percentage of protease causes further changes to occur which converts cysteic acid into cysteine monoxides of vibrational bands at 1073 [cm.sup.-1] and 1075 [cm.sup.-1] for 6% and 9% protease all at pH 4.
As seen in Figure 3, after an 88-day interval, the increase for cysteic acid and cystine dioxide is significantly higher than for other S-species.
Under these experimental conditions, the cysteinyl residue of the [alpha]T-12 peptide was oxidized to a cysteic acid residue, yielding a mass difference of -47.985 Da (see Fig.
Sulfur amino acids were determined after performic acid oxidation (Moore, 1963) as cysteic acid and methionine sulphone.
Methionine and cystine were determined as methionine sulfone and cysteic acid after cold performic acid oxidation overnight and hydrolyzing with 7.5 N HCl at 110[degrees]C for 24 h using an Amino Acid Analyzer (Hitachi L-8800, Japan).
Cystine and cysteine are oxidized to cysteic acid and cysteine sulphenic acid [16].
Furthermore, the FTIR indicated that there are 59% and 33% increases of cysteic acid of bleached hair and alkaline treated hair, respectively.