Consumption of peptide-derived arginine by a periodontopathogenic bacterium, Porphyromonas gingivalis

The specificity of amino acid consumption by Porphyromonas gingivalis, well known as an important pathogen of adult periodontitis, is described. P. gi ngivalis is an asaccharolytic, black-pigmented and gram-negative anaerobe a nd produces several types of proteases including cysteine proteases. such a s arg-gingipain and trypsin-like enzyme. This suggests that arginine is a p ossible energy source for its growth. When P. gingivalis was grown anaerobi cally in brain-heart infusion broth, several free amino acids such as lysin e, glycine and glutamic acid increased in the culture supernatant with the bacterial growth; but free arginine increased first and then started to dec rease after the early log phase. Citrulline and ornithine increased to late log phase in contrast to the decrease of arginine. The total arginine in t he medium decreased steadily with the growth of P. gingivalis. In relation to the arginine consumption, cell extracts of P. gingivalis clearly demonst rated enzyme activities for the arginine deiminase pathway and adenosine tr iphosphate production. The arginine deiminase pathway was also presumed fro m the presence of putative homologue corresponding to the other bacterial a rginine deiminase pathway relating enzymes in the unfinished P. gingivalis W83 genome. These results suggest that P. gingivalis catabolizes arginine w hich is released from proteins and/or peptides. by several types of proteas es, and obtains energy through the arginine deiminase pathway. (C) 2001 Aca demic Press.