|Detection of Human TRACP/PAP/ACP5 by Western Blot. Western blot shows lysates of human lung tissue, SK‑Mel‑28 human malignant melanoma cell line and Recombinant Human TRACP/PAP/ACP5 (Catalog # 3948-AP). PVDF membrane was probed with 0.5 µg/mL of Sheep Anti-Human TRACP/PAP/ACP5 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF3948) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). A specific band was detected for TRACP/PAP/ACP5 at approximately 36 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
Encoded by the ACP5 gene, Tartrate Resistant Acid Phosphatase (TRACP or TRAP) is also known as Purple Acid Phosphatase (PAP) or Acid Phosphatase 5 (ACP5) (1). The deuced amino acid (aa) sequence of human ACP5 predicts a signal peptide (aa 1 to 21) and a mature chain (aa 22 to 325). R&D Systems' recombinant human ACP5 consists of aa 22 to 320, without the last 5 residues, RRARP.
ACP5 is expressed at high levels by osteoclasts, macrophages and dendritic cells (2). Two forms, 5a and 5b, circulating in human blood, are derived from different cell types and have different functions. Derived from macrophages and dendritic cells, 5a is a marker of inflammatory conditions. Derived from osteoclasts, 5b is a marker of bone resorption. Compared to 5a, 5b does not contain sialic acid residues, has a higher specific activity and pH optimum, and may be processed into a disulfide-linked dimer (3).