Leucine-Rich Alpha-2-Glycoprotein Human, Sheep Polyclonal Antibody

Research topic

Sepsis

Summary

Leucine-rich alpha-2-glycoprotein (LRG) is a secretory type 1 acute phase protein whose expression is upregulated by the mediators of acute-phase response. The level of LRG in the blood increases during microbial infections and cancer, presumably as a result of the liver’s response to pro-inflammatory cytokines . The function of LRG is unknown but it is proved that LRG is tightly binding to Cyt C. It is suggested that extracellular Cyt C that is released from the cell death by an acute inflammation could be trapped to form tight complex with LRG and be excluded from circulation. LRG secretion by human hepatoma cells is increased by treatment with a mixture of cytokines including IL-6, IL-1b, and TNFα that are known to induce acute-phase proteins. It is known that LRG plays a role in adhesive interactions between lymphocytes and the endothelium. LRG may aid in the control of granulopoiesis by helping to modulate the surface expression of different receptor types, including transforming growth factor receptor, granulocyte-macrophage colony-stimulating factor receptor and possibly the macrophage colony stimulating factor receptor. LRG normal plasma concentration is approximately of 21 µg/ml based on purification, or ~50 µg/ml measured by ELISA. Human LRG is a serum glycoprotein of 312 amino acids in length with a predicted unmodified molecular weight of 34 to 36 kDa. SDS PAGE results show LRG molecular weight ranges from 44 to 55 kDa with isoelectric points ranging from 4.52 to 4.72, suggesting that 3 of 30 modifications occur. Leucine-rich alpha-2-glycoprotein consists of a single polypeptide chain with one galactosamine and four glucosamine oligosaccharides attached. The polypeptide has two intrachain disulfide bonds and contains 312 amino acid residues of which 66 are leucine. The amino acid sequence can be exactly divided into 13 segments of 24 residues each, eight of which exhibit a periodic pattern in the occurrence of leucine, proline, and asparagine.