Relaxin-2 Antibody Host:Rabbit Antibody Type:Polyclonal Species Reactivity:Human Application:Western blot Western blotting (0.5-4 μg/ml). However, the optimal conditions should be determined individually. The antibody recognizes ~21 kDa Relaxin-2 in samples from human origins. Reaction to other species has not been tested. A ~100 kDa unknown band can also be detected.