Granulocyte macrophage colony-stimulating factor (GM-CSF) is
He paper: HCT DLB HJK.
Granulocyte macrophage colony-stimulating factor (GM-CSF) is a cytokine important for the stimulation of proliferation, differentiation and survival of many hemopoietic cells [1] including mature neutrophils, macrophages and dendritic cells [2,3]. GM-CSF is produced by many cell types within the body (e.g. fibroblasts, endothelial cells) when stimulated by microbial products or inflammatory cytokines and its activity is important to the innate immune response. T lymphocytes also produce it when stimulated with a specific antigen. As well, because of its ability to stimulate hemopoietic cells, recombinant human GMCSF (rhGM-CSF) is used, for instance, as a biotherapeutic for immunocompromised individuals undergoing chemotherapy [4]. Dysregulation of GM-CSF activity has been implicated in such auto-immune conditions as arthritis and multiple sclerosis [5]. Neutralization of the bioactivity of GM-CSF by auto-antibodies causes another auto-immune disease, idiopathic pulmonary alveolar proteinosis [6] and GM-CSF is used to treat this condition [7,8]. GM-CSF is a 127 amino acid compact glycoprotein composed of a two-stranded antiparallel b-sheet and a four a-helix bundle [9]. To purify significant amounts of rhGM-CSF, many attempts have been made to express the protein in E.coli. However, with many over-expression systems it was found that rhGM-CSF formed inclusion bodies [10,11]. Inclusion bodies are aggregates of improperly folded intermediates of proteins that are often formed when mammalian proteins are expressed in E. coli and are an ongoing issue in biotechnology and biomedical research [12,13]. Advancements in inclusion body resolubilization and protein refolding have led to a better understanding of the forces governing inclusion body formation and of methods used to efficiently refold proteins of interest [14,15]. To generatea sufficient amount of purified protein from inclusion bodies it is necessary to isolate the inclusion bodies from the E. coli lysate, HA15 biological activity solubilize the inclusion bodies and then refold the protein of interest [12]. The first two steps are relatively straightforward often requiring mechanical disruption (e.g. French Press or sonication) and centrifugation to lyse the E. coli and isolate the inclusion bodies followed by the addition generally of chaotropic agents (e.g. GuHCl or Urea) to solubilize them. It is the refolding of the protein of interest that is often the limiting step with aggregation and improper disulphide bond formation being two major issues to overcome. During protein refolding, aggregation of 1407003 partially folded intermediates can result in a significant decrease in final yields. L-arginine, a natural amino acid, is commonly used to enhance protein refolding by suppressing protein aggregation [16,17]. To aid in proper disulphide bond formation, the inclusion bodies are first solubilized in a solution containing a reducing agent such as DTT or 2-mercaptoethanol. These are used to disrupt any non-native disulphide bonds and must be removed, often by dialysis, before proper disulphide bond formation can proceed in the refolding process. During refolding, a combination of IKK 16 reduced and oxidized thiols (e.g. glutathione), are used to promote disulphide exchange [12]. It is thought that this is most effective when the protein is forming its secondary and tertiary structure so that the cysteinyl residues are in the correct proximity to each other [18]. We describe in detail here a straightf.Granulocyte macrophage colony-stimulating factor (GM-CSF) is
He paper: HCT DLB HJK.
Granulocyte macrophage colony-stimulating factor (GM-CSF) is a cytokine important for the stimulation of proliferation, differentiation and survival of many hemopoietic cells [1] including mature neutrophils, macrophages and dendritic cells [2,3]. GM-CSF is produced by many cell types within the body (e.g. fibroblasts, endothelial cells) when stimulated by microbial products or inflammatory cytokines and its activity is important to the innate immune response. T lymphocytes also produce it when stimulated with a specific antigen. As well, because of its ability to stimulate hemopoietic cells, recombinant human GMCSF (rhGM-CSF) is used, for instance, as a biotherapeutic for immunocompromised individuals undergoing chemotherapy [4]. Dysregulation of GM-CSF activity has been implicated in such auto-immune conditions as arthritis and multiple sclerosis [5]. Neutralization of the bioactivity of GM-CSF by auto-antibodies causes another auto-immune disease, idiopathic pulmonary alveolar proteinosis [6] and GM-CSF is used to treat this condition [7,8]. GM-CSF is a 127 amino acid compact glycoprotein composed of a two-stranded antiparallel b-sheet and a four a-helix bundle [9]. To purify significant amounts of rhGM-CSF, many attempts have been made to express the protein in E.coli. However, with many over-expression systems it was found that rhGM-CSF formed inclusion bodies [10,11]. Inclusion bodies are aggregates of improperly folded intermediates of proteins that are often formed when mammalian proteins are expressed in E. coli and are an ongoing issue in biotechnology and biomedical research [12,13]. Advancements in inclusion body resolubilization and protein refolding have led to a better understanding of the forces governing inclusion body formation and of methods used to efficiently refold proteins of interest [14,15]. To generatea sufficient amount of purified protein from inclusion bodies it is necessary to isolate the inclusion bodies from the E. coli lysate, solubilize the inclusion bodies and then refold the protein of interest [12]. The first two steps are relatively straightforward often requiring mechanical disruption (e.g. French Press or sonication) and centrifugation to lyse the E. coli and isolate the inclusion bodies followed by the addition generally of chaotropic agents (e.g. GuHCl or Urea) to solubilize them. It is the refolding of the protein of interest that is often the limiting step with aggregation and improper disulphide bond formation being two major issues to overcome. During protein refolding, aggregation of 1407003 partially folded intermediates can result in a significant decrease in final yields. L-arginine, a natural amino acid, is commonly used to enhance protein refolding by suppressing protein aggregation [16,17]. To aid in proper disulphide bond formation, the inclusion bodies are first solubilized in a solution containing a reducing agent such as DTT or 2-mercaptoethanol. These are used to disrupt any non-native disulphide bonds and must be removed, often by dialysis, before proper disulphide bond formation can proceed in the refolding process. During refolding, a combination of reduced and oxidized thiols (e.g. glutathione), are used to promote disulphide exchange [12]. It is thought that this is most effective when the protein is forming its secondary and tertiary structure so that the cysteinyl residues are in the correct proximity to each other [18]. We describe in detail here a straightf.
