Bone metabolism is mutually balanced between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Two enzymes involved in bone metabolism, tartrate-resistant acid phosphatase (TRACP) and alkaline phosphatase (ALP), are used as markers of osteoclasts and osteoblasts, respectively.
TRACP is expressed in osteoclasts, neurons, and activated macrophages. Overexpression of TRACP has been associated with disease states such as Gaucher's disease, B- and T-cell leukemias, and osteoporosis. TRACP and ALP staining enables effective discrimination between osteoblast and osteoclast bone cells.
Alternate name for TRACP include TRAP, tartrate-resistant acid phosphatase type 5, TR-AP, trATPase, acid phosphatase type V, type 5 acid phosphatase, and tartrate-resistant acid ATPase.
Alternate names for ALP include AKP2, alkaline phosphatase, alkaline phosphatase liver/bone/kidney isozyme antibody, Alpl, AP-TNAP, HOPS, Liver/bone/kidney isozyme, PHOA, PPBT_HUMAN, tissue nonspecific alkaline phosphatase, tissue nonspecific ALP, tissue-nonspecific isozyme, TNAP, and TNSALP.
Kits for TRACP and ALP Detection
The TRACP and ALP Double Stain Kit (Cat. # MK300) combines the non-soluble, chromogenic substrates for ALP and TRACP with a nuclear staining reagent. This enables osteoblast and osteoclast detection due to the simultaneous cell staining for both alkaline and acid phosphatase activities. Detection of both enzyme markers provides a means to study the differentiation of bone cells. The kit substrates are provided as premixed reagents for ease of use. Sufficient reagents are supplied for staining approximately five culture plates (24-well format).
An alternative option for the study of bone metabolism is the TRACP and ALP Assay Kit (Cat. # MK301), which contains a soluble substrate that is quickly assayed by absorbance measurement. Either bone metabolism kit may be selected depending on user interest.
The TRACP and ALP Assay Kit allows for the simultaneous detection of both ACP (acid phosphatase) and ALP (alkaline phosphatase) enzymes via pNPP (p-nitro-phenyl phosphate) substrate. The addition of tartaric acid into the ACP assay allows for differentiation of TRACP from ALP activity. Because the TRACP and ALP Assay Kit utilizes an aqueous substrate, quantification of enzyme activities can be accomplished quickly by measuring the absorbance of the reactant.
Antibodies for TRACP and ALP Detection
The anti-TRACP polyclonal antibody (Cat. # M183) reacts against the C-terminal peptide of rat Tartrate-Resistant Acid Phosphatase (TRACP). Raised in rabbit, it is suitable for Western blot (WB) analysis and immunohistochemical (IHC) analysis of paraffin-embedded and frozen tissue sections.
The Bone Specific Alkaline Phosphatase (Rat), Polyclonal antibody (Cat. # M190) was raised against a conjugate of the KLH immunogen and the peptide (20–49), which is highly conserved between human and rat bone-specific ALP. The antibody is suitable for Western blot (WB) analysis (in non-reducing conditions) and immunohistochemical (IHC) detection of paraffin-embedded tissue sections (no antigen retrieval needed).