Among the proteins secreted from Lactobacillus acidophilus KCTC 3151, a 36 kDA and 24 kDa protein, whose amounts were relatively abundant, were purified and their N-terminal amino acid sequences determined. The N-terminal amino acid sequence of 36 kDa protein exhibited high homology with thymidine phosphorylase and glyceraldehyde-3-phosphate dehydrogenase. The N-terminal amino acid sequence of the 24 kDa protein did not show significant homology with proteins in Protein Data Base nor Gene Bank. Nucleotide sequence of the gene encoding 36 kDa protein indicates that the protein possesses the domains for a-helical, phosphate binding and pyrimidine binding sites, which are also shown in thymidine phosphorylases. Also, the protein contains conserved domains of dehydrogenase II and III. However, the activity of thymidine phosphorylase or glyceraldehyde-3-puospnate dehydrogenase could not be detected in the purified fractions of the 36 kDa protein.