passages.id: split_5_test_2634_passage
passages.type: progene_text
passages.text: Other differences from SERCA1a with respect to the overall ATPase reaction were an alkaline shift of the pH optimum , increased catalytic turnover rate at pH optimum ( highest for SERCA3b , the isoform with the longest C terminus ) , and an increased sensitivity to inhibition by vanadate that disappeared under equilibrium conditions in the absence of Ca(2+) and ATP .