these results suggest that the difference between the heavy and light sr ca2 ( + ) -atpase in the ca2+ dissociation kinetics is most probably produced by a ruthenium-red-sensitive interaction of the ca2 ( + ) -atpase with additional protein ( s ) , which is/are present exclusively in the heavy sr , rather than being due to a difference inherent to the ca2 ( + ) -atpase polypeptide itself .
C0916181
sr ca2
C0001476
ca2