Table I. Advances of membrane protein gel-free digestion methods. MSP, membrane scaffold protein; FDD, flow/detergent-facilitated protease and de-PTM digestions for deep sequencing. st, StageTip; iodoaa, iodoacetamide; ovnt, overnight (14 h); N-glyco, N-glycosylation; med, medium; id, identify; qt, quantify; hp, human proteome search.

^a Sequence coverage also depends on HPLC method and sequence database used for search.

^b Purified protein searched against specified sequence.

^c Identified by searching against human proteome (original, downloaded May, 23, 2013 from Ensembl) at peptide FDR <1%, using SEQUEST-HT and Percolator in PD 1.4. Signaling peptide sequence was not removed (a “/95%” correction, assuming a 20-residue signaling peptide for a total 500-residue protein). MSP, membrane scaffold protein; FDD, flow/detergent-facilitated protease and de-PTM digestions for deep sequencing; st, StageTip; iodoaa, iodoacetamide; ovnt, overnight (14 h); N-glyco, N-glycosylation; med, medium; id, identify; qt, quantify; hp, human proteome search.