5-OG488 acid [equivalent to Oregon Green(R) 488 carboxylic acid, 5-isomer]

Ex: 496 nm. Em: 524 nm. Soluble in: DMSO. 5-OG488 acid is the same molecule to Oregon Green® 488 carboxylic acid, 5-isomer (Oregon Green® is the Trademark of Invitrogen). This fluorinated analog of fluorescein has higher photostability and a lower pKa ~ 4.7 while 5-FAM has pKa ~6.4. The decreased pKa of 5-OG488 makes its fluorescence essentially pH insensitive in the physiological pH range. This amine-reactive 5-OG488 can be used to make bright green fluorescent bioconjugates with excitation/emission maxima ~496/524 nm. It is an excellent replacement to 5-FITC that has severe pH dependence and low photostability.