Figure 2.

Identification of yeast protein ILV5 by automated MALDI mass spectrometry and automated data base searching. Ion signals whose measured masses match calculated masses of protonated tryptic peptides, (M + H)⁺, within 50 ppm are indicated with circles. Terminal sequence tags (35) are marked by arrows and with the amino acid producing the ragged end pattern. (Inset) A magnification of one of the tryptic peptide peaks showing isotopically resolved signals differing by 1 Da due to the natural ¹³C abundance. Sequence coverage is greater than 70 percent. Average absolute mass accuracy is 25 ppm and average resolution is 10,000. Some of the unmarked peaks are matrix related, some are trypsin autolysis products and two matching peptides are outside the mass range shown.