IN-VITRO ATP-DEPENDENT F-ACTIN SLIDING ON MYOSIN IS NOT INFLUENCED BYSUBSTITUTION OR REMOVAL OF BOUND NUCLEOTIDE

To examine possible role of F-actin-bound nucleotide in ATP-dependent actin-myosin sliding, we prepared various actin filaments with differe nt nucleotide contents and compared their sliding velocities on heavy mero-myosin in the presence of 2'-deoxyadenosine 5'-triphosphate (dATP ) to exclude possible exchange of external ATP with the actin-bound nu cleotide. Neither the sliding velocity nor the length of the actin fil aments was significantly influenced by substitution or removal of acti n-bound nucleotide, indicating that actin-bound nucleotide may not pla y a significant role in the sliding between actin and myosin.