Description
Alpha-1-Antitrypsin (A1AT), also known as alpha-1 protease inhibitor (A1PI), is a glycosylated 394 amino acid 52 kDa plasma serpin that is the most abundant proteinase inhibitor in plasma. Although it does inhibit trypsin and similar proteinases, its physiological target is neutrophil elastase. Individuals with genetically low expression of A1AT are at risk for tissue and organ damage due to unchecked neutrophil elastase activities. A1AT deficiency is associated with respiratory complications such as chronic obstructive pulmonary disease. Mutations in A1AT can lead to non-functional proteins that polymerize and accumulate in the liver as in infantile hepatic cirrhosis. These conditions are life threatening and require regular injections of purified A1AT from human plasma. The sensitive quantitative measurement of total human A1AT antigen in plasma, serum, saliva, and urine is easily performed with this 96 well strip format ELISA kit. Free and complexed A1AT will be detected by the assay. The average concentration of A1AT in normal human plasma and serum is 1.3 ng/ml. The assay measures total human A1AT in the 0.1-100 ng/ml range. Samples giving human A1AT levels above 100 ng/ml should be diluted in blocking buffer before use. A 1:200,000 to 1:2,000,000 dilution for normal human plasma and serum samples, 1:10 dilution for urine samples, and no dilution for saliva is suggested for best results.
Human A1AT will bind to the affinity purified capture antibody coated on the microtiter plate. Complexed and free A1AT will react with the antibody on the plate. After appropriate washing steps, biotinylated polyclonal anti-human A1AT primary antibody binds to the captured protein. Excess primary antibody is washed away and bound antibody, which is proportional to the total A1AT present in the samples, is reacted with horseradish peroxidase conjugated streptavidin. Following an additional washing step, TMB substrate is used for color development at 450nm. A standard calibration curve is prepared along with the samples to be measured using dilutions of human A1AT. Color development is proportional to the concentration of A1AT in the samples. All reagents and standards are provided in these ELISA kits