Abstract: Compositions, such as liquid therapeutic or diagnostic compositions, and methods for their preparation and involving their use. The compositions comprise an effective amount of gelatin from cold water fish skin as a protein base. The indicated gelatin provides many significant advantages and improvements, including for instance its high stabilizing effect on labile organic substrates included in the compositions, and its low temperature gelling properties which provide improved compositions which do not substantially gel during refrigeration. Further representative advantages relate to its behavior as a zwitterion thus reducing or eliminating needs for buffers, and its surprising behavior similar to human serum protein in protein analyses such as the biuret procedure.