Ras, a 21 kDa protein, regulating a variety of biological response pathways that include cell growth, cell transformation and tumor invasion. Like other small GTPases, Ras regulates molecular events by cycling between an inactive GDP-bound form and an active GTP-bound form. In its active (GTP-bound) state, Ras binds specifically to the Ras-binding domain (RBD) of Raf1 to control downstream signaling cascades. Raf RBD Agarose beads (pink in color) are easy to visualize, minimizing potential loss during washes and aspirations of Ras-GTP pulldown.