Table 2.

Observed LC-MS/MS peaks of trypsin-digested recombinant HT-CpeBA peptides

ND represents peptides that were not detected, and Unmod represents unmodified peptides that lack a PEB chromophore. BA, pCpeBA; S, pCpeS; SF, pCpeSF2; F, pCpeF2; Z, pNT-CpeZ3; YZ, pNT-CpeYZ.

Samplea	α-82	α-139	β-80	β-165	β-48/59 (% PEB)b
BA+S+PEB	ND	Unmod	PEB	Unmod	Unmod (0)
BA+SF+PEB	Unmod	Unmod	PEB	Unmod	PEB (14.1)
BA+F+Z+PEB	Unmod	Unmod	Unmod	ND	PEB (12.5)
BA+F+YZ+PEB	PEB	Unmod	Unmod	Unmod	PEB (2)
BA+SF+Z+PEB	Unmod	Unmod	PEB	Unmod	PEB (18.1)
BA+SF+YZ+PEB	PEB	Unmod	PEB	Unmod	PEB (35.6)

^a See Fig. S3 for sample descriptions.

^b Values in parentheses represent the estimated percentage of β-48/59 peptides chromophorylated with PEB relative to non-chromophorylated β-48/59 peptides based upon the integrated intensities for the various charge states and missed cleavages or non-enzymatic modifications (e.g. addition of BME, oxidation of methionine, and internal disulfide bond).