Recombinant Proteins
The spike (S) glycoprotein of coronaviruses is essential for binding of the virus to the host cell at the beginning of the infection process. The severe acute respiratory syndrome-coronavirus (SARS-CoV) spike (S) glycoprotein is responsible for membrane fusion and is therefore required for virus entry and cell fusion. The target protein is also a major immunogen and a possible target for entry inhibitors.
The SARS-CoV-2 spike (S) protein is a large type I transmembrane protein composed of two subunits, S1 and S2. The S1 subunit contains a receptor-binding domain (RCB) responsible for binding to the host cell receptor angiotensin-converting enzyme 2 (ACE2). The S2 subunit mediates fusion between the viral and host cell membranes. The S1 RBD protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity.
HER2/neu/ErbB-2 (human epidermal growth factor receptor 2) is a membrane glycoprotein of the ErbB family of tyrosine kinase receptors. This protein family members (ErbB1-4) serve as receptors for epidermal growth factor. ErbB2 is found on the on the surface of epithelial cells and strongly overexpressed on the membrane of cancer cells especially breast cancer cells. ErbB2 has no identified ligand but rather forms heterodimers with one the other ErbB receptors. These complexes are of high affinity to its ligands. By binding of the ligand a conformational change of the cytoplasmatic tyrosine kinase part of the ErbB2 receptor results in phosphorylation of the initial PI3K/Akt signal transduction cascade protein and effects cell proliferation. Human ErbB2 consists of 1255 amino acids (aa) with a 21 aa leader sequence, a 631 aa extracellular domain (ED), a 23 aa transmembrane region, and a 580 aa cytoplasmatic domain. The soluble ED can be shed proteolytically from the cell surface, is strongly glycosylated and of a MW of 95-105 kDa. Sequence data: TQVCTGTDMKLRLPASPETHLDMLRHLYQGCQVVQGNLELTYLPTNASLSFLQDIQEVQGYVLIAHNQVRQVPLQRLRIVRGTQLFEDNYALAVLDNGDPLNNTTPVTGASPGGLRELQLRSLTEILKGGVLIQRNPQLCYQDTILWKDIFHKNNQLALTLIDTNRSRACHPCSPMCKGSRCWGESSEDCQSLTRTVCAGGCARCKGPLPTDCCHEQCAAGCTGPKHSDCLACLHFNHSGICELHCPALVTYNTDTFESMPNPEGRYTFGASCVTACPYNYLSTDVGSCTLVCPLHNQEVTAEDGTQRCEKCSKPCARVCYGLGMEHLREVRAVTSANIQEFAGCKKIFGSLAFLPESFDGDPASNTAPLQPEQLQVFETLEEITGYLYISAWPDSLPDLSVFQNLQVIRGRILHNGAYSLTLQGLGISWLGLRSLRELGSGLALIHHNTHLCFVHTVPWDQLFRNPHQALLHTANRPEDECVGEGLACHQLCARGHCWGPGPTQCVNCSQFLRGQECVEECRVLQGLPREYVNARHCLPCHPECQPQNGSVTCFGPEADQCVACAHYKDPPFCVARCPSGVKPDLSYMPIWKFPDEEGACQPCPINCTHSCVDLDDKGCPAEQRASPLTS
L-Asparaginase is an enzyme that depletes L-Asparagine an important nutrient for cancer cells resulting in cancer/tumor cell starvation. L-asparaginase is an anti-tumor agent derived from E.coli., which can inhibit the growth of malignant cells. It is used mainly for the induction of remission in acute lymphoblastic leukaemia. Because of the lymph node origin of malignant B cells in Multiple Myeloma, L-Asparagine is an essential amino acid for their cell metabolism, and, consequently, L-Asparaginase may be of value in managing the disease. The rationale behind asparaginase is that it takes advantage of the fact that ALL cells are unable to synthesize the non-essential amino acid asparagine whereas normal cells are able to make their own asparagine. These leukemic cells depend on circulating asparagine. Asparaginase however catalyzes the conversion of L-asparagine to aspartic acid and ammonia. This deprives the leukemic cell of circulating asparagine. L-Asparaginase produced from E.Coli has 303 amino acids and a molecular mass of 31731 Dalton.
Epithelial Cell Adhesion Molecule (EpCAM) also known as antigen GA733-2 is a 40 kDa transmembrane glycoprotein . It´s composed of a 242 aa extracellular domain (ED), a 23 aa transmembrane region and a 26 aa cytoplasmatic region. EpCAM is expressed is expressed in embryonic tissues and during pancreas and liver development. It functions as homotypic cell-cell adhesion molecule. In adenocarcinomas it is significantly overexpressed. EpCAM is involved in cell signaling, migration, proliferation and differentiation. The soluble, extracellular domain exists in two glycosylated forms of 32 kDa and 39kDa.
Vitronectin is a multifunctional glycoprotein present in blood and in the extra-cellular matrix. It is an important participant in a large variety of biological functions. These include cell attachment, spreading, migration, blood coagulation, plasminogen activation, fibrinolysis, and the regulation of complement function. Recombinant human vitronectin (rhnVN) from Genaxxon is a recombinant human protein that provides a defined surface for feeder-free culture of all sorts of cells including pluripotent stem cells (PSCs). When used with the appropriate chemical defined serum-free medium vitronectin has been proven to maintain pluripotency and normal growth characteristics in multiple PSC lines. rHu VN is of defined composition avoiding the lot to lot variability of plasma derived VN or extracts of EHS tumor tissue. It is produced from stable HEK cells capable of post-translational modfication (PTM) and processing which are conferring the protein superior quality regarding biologic activity and protein stability. Due to recombinant production upscaling is possible enabling large yields. The complete open reading frame of Vitronection encodes for 459 amino acids which are preceded by a 19 amino acid signal peptide. It contains three glycosilation sites and its carbohydrate moiety contributes about 30% to this molecular mass.
Lysostaphin, an endopeptidase specific for the cell wall peptidoglycan of staphylococci, is an extremely potent anti-staphylococcal agent. Lysostaphin is used as a research and diagnostic tool. Because it lyses staphylococci efficiently, it is widely used when preparing staphylococcal DNA or other cellular components for genetic and biochemical studies and for the preparation of protoplasts for transformation. Preparation and analysis of bacterial DNA has become a powerful tool used by clinical and other microbiologists in epidemiological studies aimed at tracing sources of infection or bacterial contamination.
Recombinant Human HSA produced in mammalians is a single, glycosylated, polypeptide chain of 585 amino acids and a molecular mass of 66441 Dalton. Albumin is synthesized in the liver as preproalbumin which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product, proalbumin, is in turn cleaved in the Golgi vesicles to produce the secreted albumin. Albumin is a soluble, monomeric protein which comprises about one-half of the blood serum protein. Albumin functions primarily as a carrier protein for steroids, fatty acids, and thyroid hormones and plays a role in stabilizing extracellular fluid volume. Mutations in this gene on chromosome 4 result in various anomalous proteins. Albumin is a globular unglycosylated serum protein of molecular weight 65,000. The human albumin gene is 16,961 nucleotides long from the putative 'cap' site to the first poly (A) addition site. It is split into 15 exons which are symmetrically placed within the 3 domains that are thought to have arisen by triplication of a single primordial domain. HSA is widely used to stabilize blood volume generally from donors but the fear of contamination such as HIV & Hepatitis has enticed great interest in the recombinant form which is identical to the natural blood. This recombinant HSA is produced in Plants as a non-glycosylated, polypeptide of 585 amino acids and a molecular mass of 67 kDa. The optimum concentration for recombinant Albumin to be used in cell culture ranges between 0.5gr to 2gr per liter.