passages.id: split_5_test_264_passage
passages.type: progene_text
passages.text: Quantitatively , the 10 ( 9 ) - fold rate acceleration produced by the MutT enzyme may be ascribed to catalysis by approximation and polarization of the attacking water by the enzyme - bound metal ion ( > or = 10 ( 5 ) - fold ) , activation of the NMP leaving group by Lys-39 ( 10 - fold ) , charge neutralization at P beta by the nucleotide - bound divalent cation ( > or = 10 - fold ) , and orientation and/or deprotonation of the attacking water by Glu-53 ( > or = 10 ( 2 ) - fold ) .