A process of preparing taurine-containing peptides of formula (I): ##STR1## comprises reacting a protected aminoacid with cysteamine or cystamine in the presence of a condensing agent, oxidizing the resulting compound and deprotection.
The first chemicalconversion of C-glycine in dipeptides into taurine has been achieved using a general substitution of a sulpho group for a halogeno or mesyl group via the corresponding amino acid 2-halogenoethyl-or 2-methanesulphonyloxyethyl-amides, each of which was prepared from the ethanolamide obtained by LiBH4 reduction of a protected dipeptide containing a C-glycine ester.
The physicochemical and immunochemical properties of fourteen taurine dipeptides (1-14) containing one of eleven neutral L-amino acids or three neutral D-amino acids were examined. These taurine peptides were synthesized by a conventional method using chemical coupling of taurine with an amino acid. Alternatively, the dipeptides (1-9) containing L-amino acid were also synthesized, with a few exceptions (10, 11), by a new method using a general substitution reaction of a sulfo group for chlorine or bromine via the β-halogenoethyl amide of each amino acid. When sodium sulfite or ammonium sulfite was used in the substitution, the new method gave pure taurine dipeptides in good yield without racemization. All the dipeptides (1-14), including naturally occurring Ser-Tau, showed high cross-reactivities with antisera against haptenic taurine or γGlu-Tau.