Principle of Method
This assay is a sandwich Enzyme Linked-Immunosorbent Assay (ELISA) for quantitative determination of human ACBP in cell culture supernatants, serum and plasma. An antibody specific for human ACBP has been precoated onto the 96-well microtiter plate. Standards (STD) and samples are pipetted into the wells for binding to the coated antibody. After extensive washing to remove unbound compounds, human ACBP is recognized by the addition of a biotinylated antibody specific for human ACBP (DET). After removal of excess biotinylated antibody, streptavidin-peroxidase (STREP-HRP) is added. Following a final washing, peroxidase activity is quantified using the substrate 3,3ʼ,5,5ʼ-tetramethylbenzidine (TMB). The intensity of the color reaction is measured at 450nm after acidification and is directly proportional to the concentration of human ACBP in the samples.
Sandwich type ELISA
Diazepam-binding inhibitor (DBI), Acyl coenzyme A (CoA) binding protein, Endozepine
Acyl coenzyme A (CoA) binding protein (ACBP) is a ubiquitously expressed 86 amino acid polypeptide that binds medium- and long-chain acyl-CoA esters with very high affinity. It plays a role as an intracellular carrier of acyl-CoA esters and regulates lipid metabolism in the cytoplasm of most cell types (1). In addition to its function within the cells as Acyl coenzyme A (CoA) binding protein, ACBP also functions as secreted protein called Diazepam-Binding Inhibitor (DBI) that can interact with the benzodiazepine-binding site of the gamma-aminobutyric acid (GABA) type A receptor, GABAAR, and modulate its activity (2). ACBP is secreted upon induction of autophagy (energy deficiency) in different organisms including mouse and human (3, 4, 5). ACBP levels correlate with human body mass index (BMI). Increasing ACBP levels in mice triggers lipogenesis, food intake and weight gain and neutralization of ACBP increases lipolysis, reduces food intake post-starvation and causes weight loss in mice.
Obese patients exhibit elevated plasma levels of ACBP, while a reduction in the ACBP mRNA and ACBP plasma protein levels is observed in these patients after an important weight loss. ACBP might be useful for the prevention or treatment of obesity and metabolic syndrome diseases.
Serum, Plasma and Cell Culture Supernatant
Serum and Plasma : 20 µL (actual amount of sample loaded in well after dilution);
Calibration Range: 0.03125 ng/ml – 2 ng/ml
Limit of Detection
Intra-assay (Within-Run) C.V.
Inter-assay (Run-to-Run) C.V.
References to Summary
(1) Long-chain acyl-CoA esters in metabolism and signaling: role of acyl-CoA binding proteins: D. Neess, et al.; Prog. Lipid Res. 59, 1 (2015)
(2) Endogenous positive allosteric modulation of GABA(A) receptors by diazepam binding inhibitor: C.A. Christian, et al.; Neuron 78, 1063 (2013)
(3) Unconventional secretion of Acb1 is mediated by autophagosomes: J.M. Duran, et al.; J. Cell Biol. 188, 527 (2010)
(4) Acyl coenzyme A binding protein (ACBP) is phosphorylated and secreted by retinal Muller astrocytes following protein kinase C activation: Z. Qian, et al.; J. Neurochem. 105, 1287 (2008)
(5) Acyl-CoA-Binding Protein Is a Lipogenic Factor that Triggers Food Intake and Obesity: J.M.B. Bravo-San Pedro, et al.; Cell Metabol. 30, 1 (2019)
(6) Acyl-CoA-binding protein (ACBP): the elusive 'hunger factor' linking autophagy to food intake: J.M.B. Bravo-San Pedro, et al.; Cell Stress 3, 312 (2019)