Properties of urophysial proteins (urophysins) from the white sucker, Catostomus commersoni.

Polyacrylamide gel electrophoresis, polyacrylamide gel electrofocusing and equilibrium dialysis studies on extracts of the urophysis of the white sucker, Catostomus commersoni, have shown the existence of a group of proteins which are specific to the urophysis and which bind two biologically active urophysial peptides, urotensin I (rat hypctensive principle) and urotensin II (fish smooth muscle stimulating principle).