Clusterin Human, Serum
Human Serum.
Greater than 90% as determined by SDS PAGE.
Description
Product Specs
Clusterin, also known as Apolipoprotein J, is a protein with a molecular weight of 75-80 kD. It exists as a heterodimer linked by disulfide bonds and is heavily glycosylated, containing approximately 30% N-linked carbohydrates rich in sialic acid. Truncated forms of Clusterin have been found to be targeted to the nucleus. The precursor polypeptide chain undergoes proteolytic cleavage to remove a 22-amino acid signal peptide and is further cleaved between residues 227 and 228, resulting in the formation of the a and b chains. These chains assemble in an anti-parallel orientation, forming a heterodimeric structure. Five disulfide bridges link the cysteine-rich centers, which are flanked by two predicted coiled-coil alpha-helices and three predicted amphipathic alpha-helices. Clusterin exhibits a high degree of sequence homology across various species, ranging from 70% to 80%. Its expression is nearly ubiquitous in mammalian tissues, and it is found in various bodily fluids, including plasma, milk, urine, cerebrospinal fluid, and semen. Clusterin interacts with a wide range of molecules, forming complexes with immunoglobulins, lipids, heparin, bacteria, complement components, paraoxonase, beta-amyloid, leptin, and others. It has been implicated in numerous biological processes, including phagocyte recruitment, aggregation induction, complement attack prevention, apoptosis inhibition, membrane remodeling, lipid transport, hormone transport and/or scavenging, and matrix metalloproteinase inhibition. Functionally, Clusterin acts as an extracellular chaperone, protecting cells from stress-induced damage caused by the accumulation of degraded and misfolded proteins. Dysregulation of Clusterin expression, both at the mRNA and protein levels, has been observed in various pathological conditions, including cancer, organ regeneration, infection, Alzheimer's disease, retinitis pigmentosa, myocardial infarction, renal tubular damage, and autoimmune diseases.
Human native Clusterin was sterile filtered at 0.4 μm and subsequently lyophilized from a solution containing 0.5 mg/ml Clusterin in phosphate-buffered saline (pH 7.5) and 5% (w/v) trehalose.
To prepare a working stock solution of 0.5 mg/ml, it is recommended to add deionized water to the lyophilized pellet and allow for complete dissolution. The product is not sterile. Before using it in cell culture, it must be filtered through an appropriate sterile filter.
Lyophilized Clusterin should be stored at -20°C. To avoid repeated freeze-thaw cycles, it is recommended to aliquot the reconstituted product. Once reconstituted, the protein remains stable at 4°C for a limited period and does not exhibit any changes for up to two weeks at this temperature.
The purity is determined to be greater than 90% based on SDS-PAGE analysis.
Human Serum.
Product Science Overview
Apolipoprotein J is a heterodimeric protein composed of two subunits linked by disulfide bonds. It is highly glycosylated, which contributes to its stability and function. ApoJ is involved in several cellular processes, such as:
- Lipid Transport: ApoJ is associated with high-density lipoproteins (HDL) and is involved in the transport of lipids in the bloodstream.
- Cell Survival: It acts as a cytoprotective agent, helping cells survive under stress conditions by inhibiting apoptosis (programmed cell death).
- Tissue Remodeling: ApoJ is involved in tissue repair and remodeling processes, particularly in response to injury or inflammation.
Apolipoprotein J has been studied extensively for its role in various diseases:
- Cardiovascular Diseases: ApoJ levels are altered in conditions such as myocardial infarction and atherosclerosis. It has been observed that glycosylated forms of ApoJ decrease during acute myocardial infarction, indicating its potential as a biomarker for cardiac events .
- Neurodegenerative Diseases: ApoJ is implicated in Alzheimer’s disease due to its role in amyloid-β aggregation and clearance. Studies have shown that recombinant human ApoJ can reduce cerebral microbleeds and neurovascular damage in models of cerebral amyloid angiopathy .
- Cancer: ApoJ expression is altered in various cancers, and it may play a role in tumor progression and metastasis.
Recent research has focused on the therapeutic potential of ApoJ. For instance, chronic treatment with recombinant human ApoJ has shown promise in reducing neurovascular damage in animal models of Alzheimer’s disease . Additionally, its role as a biomarker for early detection of cardiac events is being explored .
