In this study, binding properties of human prorenin to rat (pro)renin receptor (r(P)RR) and rat prorenin to human (pro)renin receptor (h(P)RR) were elucidated in vitro to investigate species specificity of prorenin bindings to (P)RR. Both (P)RRs were expressed in vitro based on wheat germ lysate and purified using His trap column. The association and dissociation rate constants of human and rat prorenin for the immobilized r(P)RR and h(P)RR were 6.64 x 10(6) and 1.01 x 10(6) M-1.s-1 and, 0.024 and 8.45 x 10(-3) s-1, respectively. Their KD values were 3.7 nM (3-fold higher than that of human prorenin vs h(P)RR (1.2 nM)) and 8.3 nM (1.2-fold lower than that of rat prorenin vs r(P)RR (10.2 nM)), respectively. Additionally, human and rat prorenin bound to the pre-adsorbed rat and human (P)RR, respectively, performed enzymatic activities. Their molecular activities were 4.1h-1 (almost similar (3.8h -1) to human prorenin vs h(P)RR) and 0.98 h-1 (approximately 2-fold lower than rat prorenin vs r(P)RR), respectively. Thus, these results suggest the species specificity for bindings of prorenin to (P)RR, which could be useful in elucidating the biochemical properties of prorenin binding to the receptor.