S-trityl-L-Cysteine is a potent inhibitor of human mitotic kinesin Eg5
In vitro, S-trityl-L-Cysteine targets the catalytic domain of Eg5 and inhibits Eg5 basal and microtubule-activated ATPase activity as well as mant-ADP release. S-trityl-L-Cysteine is a tight binding inhibitor (estimation of K(i,app) <150 nm at 300 mm NaCl and 600 nm at 25 mm KCl). S-trityl-L-Cysteine binds more tightly than monastrol because it has both an approximately 8-fold faster association rate and approximately 4-fold slower release rate (6.1/microM/s and 3.6/s for S-trityl-L-Cysteine versus 0.78 /microM/s and 15/s for monastrol). S-trityl-L-Cysteine inhibits Eg5-driven microtubule sliding velocity in a reversible fashion with an IC50 of 500 nm.