Compounds having an isolated peptide consisting of structure (I)
A new compound inhibiting phosphorylation of Ser727 of STAT3, a phosphorylation inhibitor containing the new compound, an insulin resistance improving agent and a preventive or therapeutic agent for diabetes; and a screening method for at least one of the insulin resistance improving agent and the preventive or therapeutic agent for diabetes.
1. A compound, comprising:
an isolated peptide consisting of the following amino acid sequence structure (I):
α-α′-β-γ-δ′-σ-δ Amino acid sequence structure (I)
where α denotes an N terminus, δ denotes a C terminus, α and α′ each denote lysine or arginine, δ and δ′ each denote leucine or isoleucine, and β, γ and σ each denote any amino acid.
2. The compound according to claim 1 ,
wherein the compound inhibits phosphorylation of Ser727 of signal transducer and activator of transcription 3 (STAT3).
3. The compound according to claim 2 ,
wherein the phosphorylation that the compound inhibits is phosphorylation performed by extracellular signal-regulated kinase 2 (ERK2).
4. The compound according to claim 2 ,
wherein the compound inhibits binding of ERK2 to the STAT3 to inhibit the phosphorylation.
5. The compound according to claim 1 , wherein the isolated peptide consists of the following amino acid sequence structure (II):
Lys-Lys-β-γ-δ′-σ-δ Amino acid sequence structure (II)
where Lys is an N terminus, δ denotes a C terminus, δ and δ′ each denote leucine or isoleucine, and β, γ and σ each denote any amino acid.
6. The compound according to claim 1 , wherein the isolated peptide consists of the following amino acid sequence structure (III):
α-α′-β-γ-Leu-σ-Leu Amino acid sequence structure (III)
where α denotes an N terminus, Leu is a C terminus, α and α′ each denote lysine or arginine, and β, γ and σ each denote any amino acid.
7. The compound according to claim 1 , wherein the isolated peptide consists of the following SEQ ID No. 1:
Lys-Lys-Tyr-Ile-Leu-Ala-Leu.
(SEQ ID No. 1)
8. The compound according to claim 1 , wherein the compound promotes formation of a homodimer of the STAT3.
9. A phosphorylation inhibitor, comprising:
a compound according to claim 1 .