Proteomics and sequence analysis of a 30-kDa saliva protein of Indonesian local goat (Capra hircus) using MALDI-TOF/TOF-MS and related techniques

Abstract

This study aimed to analyze and sequence a protein with molecular weight of approximately 30 kDa found in the saliva of the Indonesian local goat (Capra hircus) using matrix-assisted laser desorption/ionization-time of flight/time of flight-mass spectrometry (MALDI-TOF/TOF-MS) and related techniques. Saliva was collected from 50 healthy male and female local goats of 4-30 months old. The results showed that the average value of the total saliva protein was 669 ± 251.293 µg/mL, in the range of 350-1550 µg/mL. Mascot search and NCBI BLAST search revealed that the peptides were "PREDICTED: short palate, lung, and nasal epithelium carcinomaassociated protein 2A-like", with Mr = 26.656 kDa and pI = 4.57, which was 100% identical to Ovis aries. In addition to this, the peptide was also closely related to "TPA: common salivary protein BSP30 form d". Overall, the peptides belong to the BPI-protein superfamily, whose major roles are in innate immunity. Whether or not the identical state of the peptide in this study with those found in several other ruminants describes an evolutionary process that is common in ruminants still needs to be studied further.