sentence: Search parameters are provided by HPRC as follows : type of search – MS / MS ion search ; enzyme – trypsin ; fixed modifications – carboxymethyl ( C ) ; variable modifications – Gln > pyro ‐ Glu ( N ‐ term Q ) and oxidation ( M ) ; mass values – monoisotopic ; protein mass – unrestricted ; peptide mass tolerance – ± 15 ppm ; fragment mass tolerance – ± 20 mmu ; max missed cleavages – 1 ; instrument type – default ; number of queries – 9983 .