Synthesis of peptides in enzymic reactions involving glutathione.

Publisher Summary The chapter discusses the synthesis and chemical properties of poly-α-amino acids Poly-α-amino acids are synthetic polymers composed of α-amino acid residues linked by peptide bonds They are prepared by polymerization of the corresponding monomers and consist, like other synthetic polymers, of mixtures of homologous macromolecules of varying chain length The preparative methods developed permit the synthesis of a large variety of α-amino acid polymers, in a wide range of average molecular weights A number of different derivatives of α-amino acids and peptides have been used as monomers for the preparation of poly-α-amino acids; the most suitable and commonly used are the N-carboxy-α-amino acid anhydrides (NCAs) These readily undergo polymerization, with carbon dioxide evolution, to yield the corresponding poly-α-amino acids The synthesis of amino acid polymers from the monomers may be accompanied by varying amounts of byproducts that should be removed, during the isolation and purification of the polymer The purification techniques applied are described in the chapter In addition, the methods used to establish the chemical constitution of the polymers and their average molecular weights are given

Synthesis and chemical properties of poly-alpha-amino acids.

N-CBO-L-Seryl-L-tyrosyl-L-serine methyl ester and L-methionyl-γ-benzyl-L-glutamate are prepared by different methods. Condensation by the hydrazideazide procedure affords N-CBO-L-seryl-L-tyrosyl-L-seryl-L-methionyl-γ-benzyl-L-glutamate, which is shown to be optically pure by leucine-aminopeptidase digestion. Transformation of the above N-CBO-tripeptide ester to the N-acetyltripeptide ester and condensation by the hydrazide-azide procedure with the above dipeptide gives N-acetyl-L-seryl-L-tyrosyl-L-seryl-L-methionyl-γ-benzyl-L-glutamate. The effects produced in the course of fissure of CBO- and benzyl-groups from peptides containing serine and methionine residues, using HBr and acetic acid, are studied.

Synthèse du N-acétyl-L-séryl-L-tyrosyl-L-séryl-L-méthionyl-γ-L-glutamate de benzyle et de peptides apparentés

Development of fatty acid analysis by high-performance liquid chromatography, gas chromatography, and related techniques

The unwanted side reactions often encountered in the synthesis of methionine containing peptides can be eliminated by a temporary conversion of the thioether function of methionine into the sulfoxide at any stage of a peptide synthesis. The sulfoxide oxygen is introduced without the formation of a sulfone when a small excess of hydrogen peroxide is used, and its elimination is easily achieved by reduction with thioglycolic acid. In contrast to the carbobenzoxy derivatives of methionine the removal of the carbobenzoxy group from the corresponding sulfoxides proceeds smoothly by mild treatment with concentrated hydrochloric acid. The synthesis of the peptide derivative H·pro-Tyr-Lys(Tos)-Met·OH, using this method, is described.

Derivate von L‐Methionin‐sulfoxyd und ihre Verwendung für Peptidsynthesen

Die Ester des Methionins und einiger anderer spezifischer Aminosauren reagieren in Gegenwart von Wasser und kauflichen Praparaten von kristallisiertem Chymotrypsin unter Bildung von Peptiden.

Eine neue enzymatische Peptidsynthese. 1. Mitteilung

Aus dem Reaktionsgemisch von DL-Methionin-isopropylester und einem Chymotrypsin-haltigen Enzympraparat sind zwei Peptide isoliert und als L-Methionyl-L-methionin bzw. L-Methionyl-L-methionyl-L-methionin identifiziert worden. Damit ist der fruhere papierchromatographische Befund bestatigt und das Vorliegen einer enzymatischen Peptidsynthese aus Aminosaureestern endgultig bewiesen.

Enzymatische Peptidsynthese. 2. Mitteilung. Isolierung von enzymatisch gebildetem L‐Methionyl‐L‐methionin und L‐Methionyl‐L‐methionyl‐L‐methionin; Vergleich mit synthetischen Produkten.

R. W. Pfister

Papers

Eine neue enzymatische Peptidsynthese. 1. Mitteilung

Enzymatische Peptidsynthese. 2. Mitteilung. Isolierung von enzymatisch gebildetem L‐Methionyl‐L‐methionin und L‐Methionyl‐L‐methionyl‐L‐methionin; Vergleich mit synthetischen Produkten.