Tryptic peptides unique to rhumAb B identified by Mascot ETS and SIEVE, respectively, at 1% spiking level.

Positive identification by SIEVE is given for ratio values >2.5; positive identification by Mascot is given for ion score values >20 using a database that contains the spiking antibody sequence.*Tryptic peptide differs in one amino acid between rhumAb A and rhumAb B.**Tryptic peptide differs in two amino acids between rhumAb A and rhumAb B.(+)These peptides gave a slightly lower score in SIEVE and Mascot respectively but still were considered as identified after manual data interpretation.