passages.id: split_4_test_976_passage
passages.type: progene_text
passages.text: Wild - type inhibitory interactions shifted apparent Ca(2+) affinity of SERCA1a by an average of - 0.34 pCa units , but four of the seven mutations in M4 led to a more inhibitory shift in apparent Ca(2+) affinity , averaging - 0.53 pCa units .