Dry peptide mixtures were dissolved with 0.1% HCOOH and subjected to nano-LC-MS analysis using aC18 nanocolumn connected in-line with a QTOF2MSsystem (Micromass). The peptides were eluted in a linear gradient of 50% CH3CN,1%HCOOH. Analysis was performed by using the BioLynx package (Micromass), and database searches were performed with the Mascot package (Matrix Science) and BLAST. Partial sequencing of the peptides viaMS–MSwas used to construct the following degenerative primers: GAP 65 DGF (5-ATGATGGTNGAYTGGGGNT TY-3) and GAP 65 DGR (5-AARTANCCIGANGTRAARTG-3), used in a RT-PCR with gastrolith epithelial disk RNA. The entire GAP 65 sequence was obtained through rapid amplification of 5 and 3 cDNA ends (RACE; Clontech SMART RACE; BD Biosciences).