Recombinant proteins for S-antigen visual arrestin are available from various sources. In humans, this protein has a Uniprot ID of P10523 and has an annotated function: 'Binds to photoactivated, phosphorylated RHO and terminates RHO signaling via G-proteins by competing with G-proteins for the same binding site on RHO (By similarity).' This protein is 405 amino acids in length and 45.2 kilodaltons in mass. This protein is encoded by the gene SAG. Other names also exist, such as: S-arrestin, 48 kDa protein, S-antigen; retina and pineal gland (arrestin), arrestin 1, retinal S-antigen (48 KDa protein), rod arrestin, rod photoreceptor arrestin. This protein is conserved in other species, including: mouse, rat, zebrafish, chimpanzee, guinea pig.