Based on the hypothesis that GAP 65 does not exert its varied range
of effects [19] alone, our next step was to look for candidate proteins
that potentially formassociations with GAP 65 within the gastrolith matrix.
For this, GMPs were separated on native-PAGE. Ten bands were detected
(Fig. 3A, n1–10), excised from the gel and trypsin-digested. The
peptides were subjected to MS analysis followed by search against our
C. quadricarinatus epithelial transcript library [29]. In this manner, several
proteins were identified in each band (Fig. 3B). Most of the identified
proteins were novel. The vast majority could be assigned and
partly characterized based on homology to annotated proteins in the
database.