Peptides containing in its amino acid chain a D-2-alkylTryptophan residue wherein the alkyl group has between one and three carbon atoms and having pharmacological activity similar to that of analogous peptides containing natural unsubstituted D-Tryptophan residues in place of the D-2-alkylTryptophan. These new peptides are more resistant to oxidative degradation which usually takes place, for example, in the presence of reactive radicals or during high energy sterilization than unsubstituted Tryptophan containing peptides. Specific peptides include His-D-2-alkyl-Trp-Ala-Trp-D-Phe-Lys-NH.sub.2, Ala-His-D-2-alkyl-Trp-Ala-Trp-D-Phe-Lys-NH.sub.2, Pyro-Glu-His-Trp-Ser-Tyr-D-2-alkyl-Trp-Leu-Arg-Pro-Gly-NH.sub.2, Pyro-Glu-His-Ser-Tyr-D-2-alkyl-Trp-Leu-Arg-Pro-NHCH.sub.2 CH.sub.3, D-Pro-Gln-Gln-D-Trp-Phe-D-Trp-2-alkyl-Trp-Met-NH.sub.2, Arg-D-Trp-N-methyl-Phe-D-2-alkyl-Trp-Leu-Met-NH.sub.2, D-Phe-Cys-Phe-D-2-alkyl-Trp-Lys-Thr-Cys-NHCH(CH.sub.2 OH)CHOHCH.sub.3 and D-Phe-Cys-Tyr-D-2-alkyl-Trp-Lys-Val-Cys-Trp-NH.sub.2.
这些肽包含一个D-2-烷基色
氨酸残基的
氨基酸链,其中烷基基团含有一到三个碳原子,并具有与含有未取代的
D-色氨酸残基的类似肽相似的药理活性。这些新肽比含有未取代色
氨酸的肽更耐氧化降解,例如,在反应性自由基存在或高能灭菌过程中通常会发生这种降解。特定的肽包括His-D-2-烷基-Trp-Ala-Trp-D-Phe-Lys-NH.sub.2,Ala-His-D-2-烷基-Trp-Ala-Trp-D-Phe-Lys-NH.sub.2,Pyro-Glu-His-Trp-Ser-Tyr-D-2-烷基-Trp-Leu-Arg-Pro-Gly-NH.sub.2,Pyro-Glu-His-Ser-Tyr-D-2-烷基-Trp-Leu-Arg-Pro-NHCH.sub.2 CH.sub.3,D-Pro-Gln-Gln-D-Trp-Phe-D-Trp-2-烷基-Trp-Met-NH.sub.2,Arg-D-Trp-N-甲基-Phe-D-2-烷基-Trp-Leu-Met-NH.sub.2,D-Phe-Cys-Phe-D-2-烷基-Trp-Lys-Thr-Cys-NHCH(CH.sub.2 OH)CHOHCH.sub.3和D-Phe-Cys-Tyr-D-2-烷基-Trp-Lys-Val-Cys-Trp-NH.sub.2。