passages.id: split_5_test_2632_passage
passages.type: progene_text
passages.text: Relative to SERCA1a , all three human SERCA3 enzymes displayed a reduced apparent affinity for cytosolic Ca(2+) in activation of the overall reaction due to a decreased E(2) to E(1) Ca(2) transition rate and an increased rate of Ca(2+) dissociation from E(1)Ca(2) .