Abstract: The present study investigated the influence of synthetic N-acyl homoserine lactones (N-acyl HSLs), signaling compounds for quorum sensing, on the growth and production of proteins in periodontopathic bacteria Porphyromonas gingivalis. N-butyryl HSL, N-hexanoyl HSL, N-heptanoyl HSL, N-octanoyl HSL and N-tetradecanoyl (myristoyl) HSL were used as synthetic N-acyl HSLs (Sigma-Aldrich). N-tetradecanoyl HSL inhibited the growth of all P. gingivalis strains used in this study in a dose-dependent manner. When we compared the SDS-PAGE profiles of sonicated samples of P. gingivalis bacterial cells cultured with/without N-tetradecanoyl HSL, we found that protein production was changing. The growth of P. gingivalis was inhibited by myristoyl coenzyme A (CoA) but did not by lauroyl CoA. These results indicated that P. gingivalis responded to auto-produced N-tetradecanoyl HSL-like molecule and slowed their growth.