Human Proprotein Convertase 9/PCSK9 Quantikine
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Quantikine® ELISA Human Proprotein Convertase 9/PCSK9 Immunoassay Catalog Number DPC900 Catalog Number SPC900 Catalog Number PDPC900 For the quantitative determination of human Proprotein Convertase Subtilisin Kexin 9 (PCSK9) concentrations in cell culture supernates, cell lysates, serum, and plasma. This package insert must be read in its entirety before using this product. For research use only. Not for use in diagnostic procedures. TABLE OF CONTENTS SECTION PAGE INTRODUCTION .....................................................................................................................................................................1 PRINCIPLE OF THE ASSAY ...................................................................................................................................................2 LIMITATIONS OF THE PROCEDURE .................................................................................................................................2 TECHNICAL HINTS .................................................................................................................................................................2 MATERIALS PROVIDED & STORAGE CONDITIONS ...................................................................................................3 PHARMPAK CONTENTS .......................................................................................................................................................4 OTHER SUPPLIES REQUIRED .............................................................................................................................................5 SUPPLIES REQUIRED FOR CELL LYSATE SAMPLES ...................................................................................................5 PRECAUTIONS .........................................................................................................................................................................5 SAMPLE COLLECTION & STORAGE .................................................................................................................................6 SAMPLE PREPARATION........................................................................................................................................................6 CELL LYSIS PROCEDURE ......................................................................................................................................................6 REAGENT PREPARATION .....................................................................................................................................................7 ASSAY PROCEDURE .............................................................................................................................................................8 CALCULATION OF RESULTS ...............................................................................................................................................9 TYPICAL DATA .........................................................................................................................................................................9 PRECISION ............................................................................................................................................................................. 10 RECOVERY.............................................................................................................................................................................. 10 LINEARITY .............................................................................................................................................................................. 10 SENSITIVITY .......................................................................................................................................................................... 11 CALIBRATION ....................................................................................................................................................................... 11 SAMPLE VALUES .................................................................................................................................................................. 11 SPECIFICITY ........................................................................................................................................................................... 12 REFERENCES ......................................................................................................................................................................... 12 PLATE LAYOUT ..................................................................................................................................................................... 13 Manufactured and Distributed by: USA R&D Systems, Inc. 614 McKinley Place NE, Minneapolis, MN 55413 TEL: 800 343 7475 612 379 2956 FAX: 612 656 4400 E-MAIL: [email protected] Distributed by: Europe | Middle East | Africa Bio-Techne Ltd. China Bio-Techne China Co., Ltd. 19 Barton Lane, Abingdon Science Park Unit 1901, Tower 3, Raffles City Changning Office, Abingdon OX14 3NB, UK 1193 Changning Road, Shanghai PRC 200051 TEL: +44 (0)1235 529449 TEL: +86 (21) 52380373 (400) 821-3475 FAX: +44 (0)1235 533420 FAX: +86 (21) 52371001 E-MAIL: [email protected] E-MAIL: [email protected] INTRODUCTION Proprotein convertase subtilisin kexin 9 (PCSK9), also named neural apoptosis-regulated convertase 1 (NARC-1), is a member of the proteinase K subfamily of subtilisin-related serine endoproteases. The full-length protein has 692 amino acids, including a signal peptide, a pro- domain, and a catalytic domain. PCSK9 is highly expressed in the liver, intestine, and kidney. It is initially synthesized as a soluble 74 kDa precursor protein. In the endoplasmic reticulum, it undergoes autocatalytic intramolecular cleavage to generate a 14 kDa pro- domain and a 60 kDa catalytic domain. These two domains remain associated when PCSK9 is secreted outside the cells (1-3). The primary physiologic function of PCSK9 is to mediate the degradation of low density lipoprotein receptor (LDL R). Early observations indicated that gain-of-function missense mutations in the PCSK9 gene can cause an autosomal dominant form of hypercholesterolemia (4, 5). The expression of PCSK9 was observed to be up-regulated by the sterol regulatory element binding proteins (SREBPs), a family of transcription factors that are responsible for the upregulation of genes involved in cholesterol and fatty acid metabolism, such as the LDL R gene (6, 7). Further experimental evidence revealed that in mice, when the PCSK9 gene was knocked out, the number of LDL R in hepatocytes increased, whereas when PCSK9 was over-expressed, the amount of LDL R protein was reduced in the liver (8, 9). In humans, genetic analyses have shown that individuals who have nonsense or loss-of-function mutations in the PCSK9 gene have significantly lower plasma LDL cholesterol levels (10, 11). These investigations clearly indicated that PCSK9 plays a key role in reducing the hepatic LDL R levels. Recently, the underlying mechanism has been uncovered: under normal physiologic conditions, the LDL R is internalized on the cell surface and directed to the endosomes in order to be recycled back to the cell surface. PCSK9 binds to the EGF domain of the LDL R and prevents LDL R from being sorted to the endosomes. Instead, the PCSK9/LDL R complex is redistributed to the lysosomes for degradation (12-14). As such, PCSK9 regulates the amount of LDL R in the circulation and modulates cholesterol levels. Serum PCSK9 concentrations have been found to be directly associated with cholesterol levels (15, 16). Since individuals with loss-of-function PCSK9 mutations have strikingly reduced risk of coronary heart diseases, PCSK9 has become an attractive drug target in recent years (17, 18). One approach is to generate small molecules that are able to interfere with PCSK9 autoactivation and its interaction with LDL R. Other approaches aiming to reduce the amounts of PCSK9 in the circulation, such as small interfering RNAs (siRNAs), have also shown promise (19, 20). The Quantikine® Human Proprotein Convertase 9/PCSK9 Immunoassay is a 4.5 hour solid phase ELISA designed to measure human PCSK9 in cell culture supernates, cell lysates, serum, and plasma. It contains NS0-expressed recombinant human PCSK9 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural PCSK9 showed linear curves that were parallel to the standard curves obtained using the Quantikine® kit standards. These results indicate that this kit can be used to determine relative mass values for natural human PCSK9. www.RnDSystems.com 1 PRINCIPLE OF THE ASSAY This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for human PCSK9 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any PCSK9 present is bound by the immobilized antibody. After washing away any unbound substances, an enzyme-linked polyclonal antibody specific for human PCSK9 is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of PCSK9 bound in the initial step. The color development is stopped and the intensity of the color is measured. LIMITATIONS OF THE PROCEDURE • FOR RESEARCH USE ONLY. NOT FOR USE