Prostate Specific Antigen (PSA)
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Scripps Laboratories is a world-leading producer and supplier of purified human Prostate Specific Antigen (PSA). Various purities and preparations are available and are listed below. Please visit each product page to view individual product specifications.
Prostate Specific Antigen (PSA), a glycoprotein of the glandular kallikrein family, is a serine protease with chymotrypsin-like enzymatic activity. It has a molecular weight of approximately 33,000-34,000 Da and is found primarily in prostate tissue and seminal fluid. Serum levels of PSA are very low in healthy individuals (0 - 4 ng/ml), but are often elevated in malignant and benign prostatic disease. As such, immunoassays for serum levels of PSA have proven useful in the diagnosis and follow-up of prostate cancer.
PSA released into circulation is present as unbound, free PSA (fPSA) or bound to serum protease inhibitors, such as α1-antichymotrypsin (ACT) and α2-macroglobulin (A2M). Research indicates that immunoassays for serum levels of PSA alone cannot be relied on to distinguish prostate cancer from benign prostatic hyperplasia (BPH). Serum levels of PSA-ACT complex are reportedly higher in patients with prostate cancer than in those with BPH. As such, measuring the ratio of PSA-ACT to fPSA in patient samples is proving valuable in the differential diagnosis os prostate cancer. In addition, immunoassays for PSA-A2M serum levels may prove valuable in prostate cancer diagnosis, but further study is required.
Free PSA (fPSA) is isolated from human seminal fluid and is supplied as a liquid in 10mM Tris, 0.1% Sodium Azide, pH 8.0 ± 0.1. The non-complexing form is purified from material used to prepare the PSA-ACT Complex. The protein concentration for P0723 is determined by immunoassay. The protein concentration for other forms is determined by A280 using an extinction coefficient of 1.86 (Emg/ml = 1.86). Both of the complexed forms are prepared by in-vitro complex formation with the purified proteins. PSA-ACT complex is supplied as a liquid in 10mM Sodium Acetate, 150mM Sodium Chloride, 0.1% Sodium Azide, pH 5.6 ± 0.1. The protein concentration is determined by A280 using an extinction coefficient of 1.0 (Emg/ml = 1.0). PSA-A2M is supplied as a liquid in 20mM Sodium Phosphate, 150mM Sodium Chloride, 0.05% Sodium Azide, pH 7.4 ± 0.1. Protein is determined using the Bradford method (BSA standard).
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