the decrease in tyrosinase stimulation by msh as cell density increases is also apparently not the result of an increase in activity of any soluble inhibitor of the enzyme , for cytosol preparations from high-density cultures ( 10 ( 5 ) cells/cm2 ) fail to inhibit tyrosinase activity in cell homogenates from low-density cultures treated with msh .
C1383501
cytosol
C0007634
cell