Src Optimal Peptide Substrate [AEEEIYGEFEAKKKK]

Product Name: Src Optimal Peptide Substrate [AEEEIYGEFEAKKKK]

Sequence One Letter Code: AEEEIYGEFEAKKKK

Sequence Three Letter Code: H-Ala-Glu-Glu-Glu-Ile-Tyr-Gly-Glu-Phe-Glu-Ala-Lys-Lys-Lys-Lys-OH

Chemical Formula:C81H127N19O27

Molecular Weight: 1799

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: peptide substrate

Conjugation: Unconjugated

Code Nacres: NA.26

Application: Src Optimal Peptide Substrate (AEEEIYGEFEAKKKK) is a synthetic sequence identified as an efficient phosphorylation target for Src family tyrosine kinases. The centrally positioned tyrosine residue serves as the phospho-acceptor site, enabling sensitive quantification of Src catalytic activity. This substrate is used in kinase profiling, enzymatic kinetics, and inhibitor screening to compare Src activity with related kinases and to investigate Src-mediated signaling pathways.

Current Research: Src Optimal Peptide Substrate (AEEEIYGEFEAKKKK) is a synthetic phosphorylation substrate identified as a highly efficient target for Src family tyrosine kinases (SFKs). The sequence was optimized to promote strong catalytic turnover by Src through favorable residue positioning around a central tyrosine phospho-acceptor site, enabling sensitive and quantitative assessment of kinase activity. Because Src kinases regulate key pathways controlling proliferation, migration, adhesion, and survival, this substrate is widely used in kinase profiling, mechanistic enzymology, and inhibitor development studies. Structural Features and Substrate Design The peptide sequence: AEEEIYGEFEAKKKK includes: A centrally located tyrosine (Y) serving as the phosphorylation site Acidic residues (E) flanking the phospho-acceptor site to enhance recognition C-terminal lysine residues (K) that improve solubility and assay compatibility The optimized sequence promotes efficient binding to the Src catalytic domain and supports robust phosphotransfer from ATP to the tyrosine residue. Biological Context Src family kinases are non-receptor tyrosine kinases involved in signal transduction downstream of: Growth factor receptors Integrins Cytokine receptors Upon activation, Src phosphorylates target proteins on tyrosine residues, regulating pathways such as: MAPK/ERK signaling PI3K/Akt signaling Focal adhesion dynamics Cytoskeletal remodeling Dysregulated Src activity is associated with oncogenesis, metastasis, and inflammatory diseases. Research Applications 1. Kinase Activity Assays The substrate is widely used to quantify Src catalytic activity in purified enzyme preparations or cell lysates. 2. Kinetic Characterization It supports determination of kinetic parameters (Km, Vmax, catalytic efficiency) under defined ATP and substrate concentrations. 3. Inhibitor Screening The peptide is suitable for evaluating Src kinase inhibitors. Reduced phosphorylation allows calculation of IC₅₀ values and comparison of inhibitor potency. 4. Comparative Kinase Profiling Because Src shares structural similarities with other SFKs, this substrate enables comparative analysis of activity among related kinases (e.g., Fyn, Yes, Lyn). 5. Signal Transduction Studies The peptide can be incorporated into assays examining regulation of Src activity in response to upstream signaling events or mutations. Detection Platforms Phosphorylation can be quantified using: Radiometric (γ-³²P-ATP) assays Anti-phosphotyrosine antibody–based detection Fluorescence or luminescence-coupled kinase assay systems Mass spectrometry for direct phosphopeptide confirmation Experimental Considerations ATP concentration and Mg²⁺ availability should be optimized to avoid rate limitation. Substrate concentration should be selected relative to Km for accurate kinetic measurements. Inclusion of selective Src inhibitors (e.g., ATP-competitive compounds) can confirm assay specificity.