Sphingosine Kinase 1 (SPK1) Antibody Host:Rabbit Antibody Type:Polyclonal Species Reactivity:Human, mouse, rat Application:Western blot Western blotting (0.5-4 μg/ml). However, the optimal concentrations should be determined individually. The antibody recognizes 42 kDa bands from samples of human, mouse and rat origins. Reactivity to other species has not been tested.