Purity ~95%. SH3 binding sequence of guanine nucleotide exchange factor hSOS; blocks binding of hSOS1 to human Grb2, preventing Ras activation via receptor protein tyrosine kinases. Grb2 acts as an adaptor protein in the transduction of signals from receptor tyrosine kinases to Ras. It binds to phosphotyrosine on the cytoplasmic tail of cell-surface receptors via its central SH2 domain, and to its immediate downstream target, Sos, via two SH3 domains. Sequence (linear): Val-Pro-Pro-Pro-Val-Pro-Pro-Arg-Arg-Arg-OH Amino Acid Analysis: Confirms expected sequence Peptide Content: 84.9 ± 4% Solubility: H2O