“…Some commercially available and commonly used for labeling fluorescent coumarins are shown in Figure 1 . Functionalized with carboxylic groups or with activated esters, coumarins ( Figure 1 ) have been aimed for detection of amino acids, small sized proteins, and antibodies through the peptide bond formation [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. 7-Diethylamino-coumarin-3-carbohydrazide is used for fluorescence labeling of carbonylated proteins and lipids [ 44 , 45 , 46 , 47 , 48 ].…”