Table 2.

Chemical and mass spectrometric sequence analysis ofLymnaea stagnalis EGF

TreatmentFragmentSequenceCalculated observations Mass Da (average)Procedures
None(1–43)4541.02-a4540.8ES-MS
4540.9MALDI
Reduced(1–43)4547.04546.9MALDI
Red. & Alk.(1–43)5177.95177.5MALDI
Red. & Alk./70% formic(7–41)       PXQIVRXSYGANXIAYGDTAIXEXPFGYSGIRXQEdman
Tr. of Red. & Alk.(1–12)1404.51404.7MALDI
1403.8ES-MS
(1–12) <QGDGEDPXQIVRES-CID
(13–38)             XSYGANXIAYGDTAIXEXPFGYSGI3155.73155.4Edman, MALDI
PGAP of (1–12)(2–12)     GDGEDPXQIV1293.41293.6Edman, MALDI
Red. & Alk./Glu-C(30–43)                              XPFGYSGIRXQDPSEdman
Sequence(1–43) <QGDGEDPCQIVRCSYGANCIAYGDTAICECPFGYSGIRCQDPS
 ‖        ‖         ‖         ‖         ‖
 1      10       20       30       40

  • 〈Q, Pyrrolidone carboylic acid; Red. & Alk., reduction and alkylation; X, pyridylethyl cysteine; Tr, trypsin; Glu-C, endoproteinase Glu-C.

  • ↵F2-a Calculated as oxidized peptide; therefore, three disulfide bonds.