Abstract: Objective: To explore the structure and function of the five lactate dehydrogenase genes and their encoded proteins from Lactobacillus plantarum LY-78. Methods: Several bioinformatic tools were used to analyze and predict the gene sequences and amino acid sequences of lactate dehydrogenase from the strain. Results: The nucleotide and amino acid sequences of the five lactate dehydrogenases in L. plantarum LY-78 were all highly conserved. The five lactate dehydrogenase proteins showed thermal stability and were non-secretory and non-transmembrane proteins, which were located in the cytoplasm. All the four genes except ldhL3 had highly conserved functional sites and domains, and contained the highly conserved sequence GXGXXG, which had typical NAD+ binding sites. Conclusion: D1-LDH, D2-LDH, L1-LDH and L2-LDH manifest complete functional sites and domains, likely having a real activity of lactate dehydrogenase. Because of the lack of NAD+ binding domain and functional sites, L3-LDH may not have lactate dehydrogenase activity. These results are important for theoretical researches of genetic modification of the lactate dehydrogenase genes and the metabolic mechanism of phenyllactic acid in L. plantarum LY-78.

Key words: Lactobacillus plantarum, lactate dehydrogenase, phenyllactic acid, bioinformatic