sentence: Digests were carried out in 200mM EPPS pH 8.5 in presence of 2 % acetonitrile ( v / v ) with LysC ( Wako , 2mg / ml at 1:75 ) for 3 hours at RT and subsequently trypsinated ( Promega , #V 5111 , stock 1:75 ) overnight at 37 ° C. Missed cleavage rate was assayed from a small aliquot by mass spectrometry .