The GABA A Receptor alpha 4 (GABA(A) receptor subunit alpha 4, GABR A4, GABRA4, Gamma aminobutyric acid (GABA) A receptor alpha 4) (Control Peptide)[GABA A Receptor alpha 4] is a α- or alpha protein sometimes glycoprotein present in blood.Isotype or positive controls by peptides, antibodies and deactivated samples.Peptides short amino acid chains or epitopes or blocking antagonists. The shortest peptides are dipeptides, consisting of 2 amino acids joined by a single peptide bond, followed by tripeptides, tetra peptides, ... till polypeptides that are long, continuous, and unbranched synthetic peptide chains. These biological oligomers and polymers can be Solid-phase peptide synthesis (SPPS), or in continue produced for custom peptide synthesis projects. The High-efficiency solid phase peptide synthesis (HE-SPPS) is give very low production costs.The receptors are ligand binding factors of type 1, 2 or 3 and protein-molecules that receive chemical-signals from outside a cell. When such chemical-signals couple or bind to a receptor, they cause some form of cellular/tissue-response, e.g. a change in the electrical-activity of a cell. In this sense, am olfactory receptor is a protein-molecule that recognizes and responds to endogenous-chemical signals, chemokinesor cytokines e.g. an acetylcholine-receptor recognizes and responds to its endogenous-ligand, acetylcholine. However, sometimes in pharmacology, the term is also used to include other proteins that are drug-targets, such as enzymes, transporters and ion-channels.