Abstract
Let R be a prime ring of characteristic not 2 with involution * and for each i=1,2, d_i be a nonzero derivation on R such that d_i(x^{*})=-(d_i(x))^{*} for all x in R. Suppose that |C|≧5 and d_1(s)d_2(s)=0 for all s in S, then R is either a commutative domain or an order in a 4-dimensional central simple algebra.