Lysine is an essential amino acid that is not only one of the fundamental building blocks of proteins, but it has been shown to play a role in calcium homeostasis and fatty acid metabolism. Our Lysine Assay Kits provide a convenient method to quantify lysine in a variety of sample types. Detection is performed in a 96-well plate with either colorimetric or fluorometric detection. Each kit provides sufficient reagents for 100 assays, including blanks, lysine standards, and unknown samples.