In our attempt to replace platinum successively by gold in CePt 5 - x Au x , we have found that with increased Au content the initial hexagonal CaCu 5 structure of CePt 5 changes into the cubic AuBe 5 structure for 1 < x 3. Since this is the same lattice as in the heavy fermion system UPt 4 Au, with U replaced by Ce, we can now compare the role of the two different elements in this configuration. We have investigated the influence of the Au content on the low temperature specific heat and magnetic susceptibility, which both increase with increasing Au content, and discuss to what extent this enhancement might be created by the electronic density of states or by magnetic entropy. Furthermore, we have studied the transition from the U-based heavy fermion system into the Ce-based system in U 1 - y Ce y Pt 4 Au.