Galactose Colorimetric Detection Kit

The Galactose Detection research-use-only kit is a colorimetric assay designed for the quantification and detection of galactose in serum, plasma, buffers and tissue culture media.

This complete, ready-to-use kit includes clear 96-well plate(s), galactose standard, assay buffer, and other components to perform the assay. A 96-well microplate reader capable of reading optical density at 560 nm is required for use of this kit.

Performance characteristics
• Assay type: colorimetric detection kit
• Sample types: serum, plasma, buffers, and tissue culture media
• Sensitivity: 0.493 mg/dL
• Standard curve range: 0.78–25 mg/dL
• Reactivity: species independent

Background
Galactose is a hexose sugar that differs from glucose only by the configuration of the hydroxyl group at the carbon-4 position. Present as an anomeric mixture of alpha-D-galactose and beta-Dgalactose, this monosaccharide exists abundantly in milk, dairy products, and many other food types such as fruits and vegetables. Absorption of galactose in humans is mediated by the Na+/glucose co-transporters SGLT1 and SGLT2 from food across the brush border membrane of the proximal jejunum and renal epithelium. Other sources of galactose include endogenous production and natural turnover of glycolipids and glycoproteins.

Inside the cells, beta-D-galactose is epimerized to alpha-D-galactose through the action of a mutarotase. Alpha-D-galactose is subsequently converted to galactose-1-phosphate (Gal-1-P) by the enzyme galactokinase. In the presence of galactose-1-phosphate uridylyltransferase, Gal-1-P reacts with UDP-glucose to form UDP-galactose and glucose-1-phosphate. Glucose-1-phosphate produced can enter the glycolytic pathway or react with UTP in the presence of UDP-glucose pyrophosphorylase to form a new molecule of UDP-glucose. This enzyme pathway comprises the evolutionarily conserved Leloir pathway of galactose metabolism.

Assay principle
The Galactose Colorimetric Detection Kit is designed to quantitatively measure galactose in a variety of samples. A D-(+)-galactose standard is provided to generate a standard curve for the assay and all samples should be read off the standard curve. Samples are mixed with the Substrate and horseradish peroxidase and the reaction initiated by addition of galactose oxidase. The plate is incubated at room temperature for 30 minutes. The galactose oxidase reacts with galactose to produce hydrogen peroxide which, in the presence of HRP, reacts with the colorless Substrate to produce a pink-colored product to be read at 560 nm. Increasing levels of galactose cause a linear increase in color.

Related links
Learn more about ELISA kits
Learn more about other immunoassays