Sentence examples for minimum ion score from inspiring English sources

Precursor mass accuracy (10 ppm), MSMS mass accuracy (0.6 Da), enzyme (Trypsin, missed cleavages = 1), Fixed modifications (Carbamidomethylation of cysteine), Variable modifications (Oxidation of methionine, phosphorylation of S, T, Y), minimum ion score = 20.

The database search criteria were as follows: trypsin; one missed cleavage site allowed; fixed modifications iTRAQ 4-plex on N-terminal and lysine ε-amino group, methylthiolation of cysteine; variable modification methionine oxidation; peptide mass tolerance of 100 ppm; MS/MS tolerance of 0.2 Da; maximum peptide rank of 1, minimum ion score C.I. (peptide) of 95%.

The searching parameters were as follows: cysteine methanethiolation, N-terminal iTRAQ labeling, and iTRAQ-labeled lysine were selected as fixed modifications; methionine oxidation was considered as a variable modification; precursor tolerance was set to 100 ppm; MS/MS fragment tolerance was set to 0.4 Da; maximum peptide rank was set to 1; the minimum ion score C. I. % was set to 1%.

The confidence interval for protein identification was set to ≥95% (p < 0.05) and only peptides with a minimum ion score of 79 were considered correctly identified.

MS/MS peptide spectra with a minimum ion score confidence interval >95% were accepted; this was equivalent to a median ion score cutoff of approximately 35 in the data set.

Mascot search results were also further processed using a local implementation of the Average Peptide Scoring (APS) method [ 26], applying both a peptide quality filter (set to a minimum ion score of 10) and a protein-level APS threshold derived from spectral matches to peptides in a reversed decoy database.

All but one identified peptide had a minimum Mascot ion score of 20, and all sites of predicted PTM were manually validated by inspection of the MS/MS spectra.

Furthermore, protein hits were taken as identified if a minimum of one peptide had an individual ion score exceeding the MASCOT identity threshold.

By MS/MS analysis, positive identifications required a minimum of two unique peptides, with at least one peptide having a significant ion score.

f) Confidence of protein score and ion score.

f Ion score for acceptance: individual ion score > 38 indicate identity or extensive homology (p < 0.05).