AffinityImmuno Products

Introduction

ANGPTL4, also known by aliases such as PGAR and fasting-induced adipose factor, is a secreted glycoprotein produced by liver, fat tissue, and placenta whose expression rises during fasting and periods of low insulin. The protein blocks lipoprotein lipase activity, a mechanism that governs how quickly triglyceride-rich lipoproteins are cleared from the bloodstream, and this places it at the center of glucose and lipid homeostasis. Proteolytic processing separates an N-terminal coiled-coil region from a C-terminal fragment containing a fibrinogen-like domain, and the two pieces appear to have separable biological roles, including effects on endothelial cell behavior such as migration and tube formation. ANGPTL4 output climbs in endothelial cells and heart muscle cells under low-oxygen conditions, and altered circulating amounts of the protein have been linked to metabolic disturbances such as type 2 diabetes.

As a fasting-induced lipoprotein lipase inhibitor produced by liver, fat, and placenta, ANGPTL4 sits alongside ANGPTL3 and ANGPTL8 in the angiopoietin-like family now being explored for metabolic disease drug targeting, and its hypoxia-inducible expression in endothelial and cardiac muscle cells also makes it relevant to vascular biology research.

Principle of the Assay

This kit uses a sandwich enzyme immunoassay format in which the microtiter plate wells are pre-coated with a capture antibody specific to Human ANGPTL4. Standards or samples are dispensed into the appropriate wells alongside a biotin-conjugated detection antibody that also recognizes Human ANGPTL4. Avidin conjugated to horseradish peroxidase (HRP) is then added to each well and allowed to incubate. Upon addition of TMB substrate solution, a colorimetric signal develops exclusively in wells where Human ANGPTL4, the biotin-conjugated antibody, and avidin-HRP are all present. The enzymatic reaction is stopped by the addition of a sulphuric acid solution, and absorbance is measured spectrophotometrically at 450 nm ± 10 nm. Human ANGPTL4 concentrations in the samples are determined by referencing the measured optical densities against a standard curve.