K-Ras Isoform B (G12C, C51S, C80L, C118S mutant, human, recombinant)

K-Ras is a small GTPase and member of the RAS family of GTPases with roles in apoptosis, as well as cell proliferation, survival, and migration. K-Ras is composed of a guanine nucleotide-binding domain containing an active site, an effector-binding domain, and an isoform-specific C-terminal hypervariable region, which varies by four amino acids between isoforms A and B. The active site cycles between GDP-bound inactive and GTP-bound active states and is regulated by its associations with GTPase-activating proteins (GAPs) or guanine nucleotide exchange factors (GEFs). K-Ras is ubiquitously expressed and is tethered to the intracellular side of cell membranes via farnesyl and palmitoyl lipidation. The glycine-to-cysteine substitution at position 12 of mutant K-Ras (K-RasG12C) is constitutively activating and found in pancreatic, colon, and lung cancers. K-RasG12C substitutions of serine, leucine, and serine for the native cysteine residues in positions 51, 80, and 118 (C51S, C80L, C118S), respectively, of the guanine nucleotide-binding domain have minimal effects on protein structure, therefore, this tetramutated protein has been used to improve labeling of Cys12 for protein crystallography and to reduce off-target inhibitor ligation and prevent cysteine-based reactions in kinetic assays. Cayman's K-Ras Isoform B (G12C, C51S, C80L, C118S mutant, human, recombinant) protein can be used for ELISA, enzyme activity assay, protein crystallography, and Western blot applications.Synonyms: c-K-ras(G12C, C51S, C80L, C118S), K-Ras4A(G12C, C51S, C80L, C118S), K-Ras Cys-light, Ki-Ras(G12C, C51S, C80L, C118S), c-Ki-ras(G12C, C51S, C80L, C118S), Kirsten Rat Sarcoma Virus(G12C, C51S, C80L, C118S). Purity: >90% estimated by SDS-PAGE. Source: Active recombinant human N-terminal His-tagged K-Ras isoform B (G12C, C51S, C80L, C118S) expressed in E. coli. Amino Acids: 1-169. MW: 22.27 kDa. Formulation: (Request formulation change), 20 mM HEPES, pH 8.0, with 150 mM sodium chloride, and 1 mM magnesium chloride. UniProt Accession #: P01116.