Table I

Total number of human hair proteins detected from the insoluble fraction of three individuals and false positive rates at the given identification criteria

The total number of validated non-redundant proteins from the three samples is 343. False positive rates given in parentheses were calculated from the proteins that passed Sequest criteria but failed to pass manual validation.

SampleTight criteria without manual validationaLoose criteriab
Before manual validationAfter manual validationcAfter further removal of redundant proteinsd
SM215 (3.2%)248 (6.9%)231221
JY258 (8.1%)310 (15.2%)263247
HR214 (2.8%)253 (11.4%)224211
  • a Tight criteria. Accepted fully tryptic peptides only. Xcorr at least 1.9, 2.2, and 3.75 for singly, doubly, and triply charged peptide ions, respectively. ΔCn at least 0.08. Identified with at least two peptides for each protein.

  • b Loose criteria. Same as tight criteria except half-tryptic peptides were also accepted.

  • c MS/MS spectra of the proteins that passed loose criteria were subjected to manual validation.

  • d Redundant proteins were further removed from manually validated proteins. Namely proteins with no unique peptide were removed. For proteins exhibiting unique peptides, at least one was manually examined for final verification.