HMW : The IRDye 680RD dye bears an NHS ester reactive group that will couple to free amino groups and form a stable conjugate with high molecular weight proteins (45 - 200 kDa).
LMW : The IRDye 680RD dye bears an NHS ester reactive group that will couple to free amino groups and form a stable conjugate with low molecular weight proteins (15 - 45 kDa).
Microscale : The IRDye 680RD dye bears an NHS ester reactive group that will couple to free amino groups and form a stable conjugate with 100 µg of protein with molecular weight 14 - 200 kDa. IRDye 680RD is the dye of choice for small animal imaging applications in the 680 nm wavelength.