Synthese einer Partialsequenz aus dem aktiven Zentrum der Streptokokken-Proteinase (EC 3.4.22.10), IX / Synthesis of a Fragment of the Active Center of the Streptococcal Proteinase (EC 3.4.22.10), IX

The synthesis of the protected pentapeptide tert-butyloxycarbonyl-Gln-Ile-Met-Lys (X) -Gly-p-nitrobenzylester (X = benzyloxycarbonyl, 3-chlor-benzyloxycarbonyl) which is part of the carboxylend of a partial sequence of the active center of the streptococcal proteinase is described. Side reactions are observed if the tert-butyloxycarbonyl-protective group is cleaved by trifluoroacetic acid, not with HCl/dioxane. Obviously the presence of methionine is responsible for the formation of by products. Formation of methioninesulfoxide or tert-butylsulfoniummethionine could not be proved. tert-butyloxycarbonyl-Gln-1-hydroxybenzotriazolylester was obtained in a crystalline state from the reaction of ferf-butyloxycarbonyl-Gln, dicyclohexylcarbodiimid and 1-hydroxybenzotriazol.