on the other hand , at 20 degrees c , at ph 8 , and in 2 mm mg2+ , the elongation rate from the slow growing end of an actin filament , measured by using the protein brevin to block growth at the fast growing end , is only 4 times slower for actin containing adp than for actin containing atp .
C0025979
actin filament
C0001271
actin