A recombinant heteromultimeric protein including at least (a) a polypeptide fusion molecule A consisting of a C4BP .alpha.-chain C-terminal fragment and a polypeptide fragment heterologous to said .alpha. chain, and (b) a polypeptide fusion molecule B consisting of a C4BP .beta.-chain C-terminal fragment and a polypeptide fragment heterologous to said .beta.-chain, wherein (a) and (b) are linked in the C-terminal portion to form said multimeric protein.