Biotinand biotin derivatives bind with high affinity to both avidins andstreptavidins. Biotin and its derivatives can be conjugated to manybiomolecules without significantly altering the biological activity of thetarget molecules since biotin is relatively a small molecule. A biopolymer(such as proteins) can react with several molecules of biotin that, in turn,can each bind one avidin. This characteristic greatly increases the sensitivityof many biological assays. Biotin derivatives are widely used for biologicaldetections and purification. This biotin derivative is carbonyl-reactive. It isused for colorimetric assays for Factor XII (when used with EDC) and cellulartransglutaminase. It is also widely used for labeling peptides (carboxylic acidgroups) and nucleotides (5� phosphate groups) via the use of EDC.