Let A and B be two unital prime complex ∗-algebras such that A has a nontrivial projection. In this paper, we study the structure of the bijective mappings Φ ∶ A → B preserving sum of products α1ab∗ + α2b∗a + α3ba∗ (resp., α1ab∗ + α2b∗a + α3a∗b), where the scalars {αk}3k =1 are rational numbers satisfying some conditions.
