passages.id: split_4_test_1279_passage
passages.type: progene_text
passages.text: Western blotting revealed absence of 2-MBCDase protein in fibroblast extracts ; DNA sequencing identified a single 778 C > T substitution in the 2-MBCDase coding region ( 778 C > T ) , substituting phenylalanine for leucine at amino acid 222 ( L222F ) and absence of enzyme activity for the 2 - MBCDase protein expressed in Escherichia coli .