Fatty acid-binding proteins (FABPs) are a class of cytoplasmic proteins that bind long chain fatty acids. FABPs are small intracellular proteins (~13-14 kDa) with a high degree of tissue specificity. They are abundantly present in various cell types and play an important role in the intracellular utilization of fatty acids, transport and metabolism. There are at least nine distinct types of FABP, each showing a specific pattern of tissue expression. Due to its small size, FABP leaks rapidly out of ischemically damaged necrotic cells leading to a rise in serum levels. Ischemically damaged tissues are characterized histologically by absence (or low presence) of FABP facilitating recognition of such areas. Intestinal FABP (I-FABP) is specifically localized in the epithelium cells of the small bowel. The I-FABP protein is derived from the human FABP2 gene. Normally, I-FABP is undetectable in serum. Many observations indicate that I-FABP is a useful biochemical marker for intestinal cell damage both in vivo and in vitro. Ischemically damaged cells are characterized histologically by absence (or low presence) of FABP facilitating recognition of areas of ischemically damaged cells.
The human I-FABP ELISA kit is to be used for the in vitro quantitative determination of human I-FABP in serum, plasma, urine and cell culture supernatant samples.
The human intestinal FABP ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours.
The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay.
Samples and standards are incubated in microtiter wells coated with antibodies recognizing human I-FABP
Biotinylated tracer antibody will bind to captured human I-FABP.
Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody.
Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB).
The enzyme reaction is stopped by the addition of citric acid.
The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the human I-FABP standards (log).
The human I-FABP concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.