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. Following acute myocardial infarction (AMI) the small protein H-FABP is rapidly released into the circulation. H-FABP is derived from the human FABP3 gene. Significantly elevated serum/plasma concentrations are found within 3 h after AMI which generally return to normal values within 12 to 24 h. These features make H-FABP a useful research tool for the early assessment or exclusion of AMI, and for the monitoring of a recurrent infarction.
Constitutive H-FABP released from the heart after AMI is quantitatively recovered in serum/plasma. Thus assessment of H-FABP is also a very effective tool for the estimation of the infarct size. The human H-FABP kit can also be used for measurement of brain-type FABP, a marker for brain injury detection and for measurement of muscle-type cytosolic fatty acid binding protein (FABPc) in skeletal muscle. In serum/plasma of healthy individuals approximately 1.6 ng/ml of H-FABP is present. H-FABP shows a slight increase with age.
The human H-FABP ELISA kit is to be used for the in vitro quantitative determination of human H-FABP in serum or plasma samples.
The human H-FABP ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 1¼ (normal) or ¾ (rapid) hours. The efficient format of 2 plates with twelve disposable 8-well strips allows free choice of batch size for the assay. Samples and standards are incubated together with peroxidase-conjugated second antibody in microtiter wells coated with antibodies recognizing human H-FABP. During incubation human H-FABP is captured by the solid bound antibody. The secondary antibodies will bind to the captured human H-FABP. The peroxidase-conjugated second antibody will react with the substrate, tetramethylbenzidine (TMB). The enzyme reaction is stopped by the addition of oxalic 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 H-FABP standards (log). The human H-FABP concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.