Abstract: The internet-based software such as the SignalP v3.0, TargetP v1.01, Big-PI predictor and TMHMM v2.0 were combined to predict the signal peptides, and the signal peptide-dependent secreted proteins among the 6700 ORFs in Saccharomyces cerevisiae genome. The results showed that 163 proteins were the secreted ones containing signal peptides among 6700 proteins, and they were secreted via Sec pathway. Among the 163 secreted proteins, the signal peptides of 47 secreted proteins only comprised by H-domain and C-domain, without N-domain, but the signal peptides of other 116 secreted proteins including the complete three domains. There were differences on constitution of signal peptides between the secreted proteins of Saccharomyces cerevisiae and ones of Candida albicans, but the length and amino acids types of their signal peptides were similar in general. There were few of the same signal peptides occurred in the secreted proteins of Saccharomyces cerevisiae genome, in order to compare the homology among the secreted proteins with the same signal peptides. The BLAST 2 SEQUENECES and CLUSTAL W were used to align the two protein sequences and multi-protein sequences, respectively. The alignment result indicated that homology of these sequences with the same signal peptide was very highly conservative in amino acid of complete gene. The effect of the signal peptides in S. cerevisia on expression of foreign eukaryotic secreted proteins was discussed in the paper.

Key words: Saccharomyces cerevisia, Secreted protein, Signal peptide, Secretory pathway