title: Salivary β-galactosidase activity affects physiological oral malodour.
abstract: OBJECTIVE
  Previous reports have associated salivary β-galactosidase activity with non-periodontopathic oral malodour. In this study, we investigated the localization of β-galactosidase and elucidated the relationship between its enzymatic activity and physiological oral malodour.
  
  
  METHODS
  Fifty-six patients complaining of halitosis were separated into two groups: periodontally healthy and periodontitis. Saliva samples from the subjects were separated by centrifugation, and the level of β-galactosidase activity was measured in the supernatant, pellet lysate, and whole saliva using the chromogenic substrate o-nitrophenyl-β-d-galactopyranoside. The correlation of salivary β-galactosidase activity with breath odour and associated parameters was examined.
  
  
  RESULTS
  Similar levels of β-galactosidase activity were detected in the pellet lysate and whole saliva, but not in the saliva supernatant. Positive correlations were observed between the β-galactosidase activity in whole saliva and oral malodour levels in the periodontally healthy group, but not in the periodontitis group. In addition, the plaque index and tongue coating score were positively correlated with β-galactosidase activity in the periodontally healthy group. Overall, stimulated salivary flow and salivary pH were negatively correlated with enzyme activity. The amounts of total bacteria, Fusobacterium nucleatum, and Streptococcus salivarius were positively associated with β-galactosidase activity in the periodontally healthy group. Furthermore, the amounts of total bacteria and S. salivarius were positively associated with the amount of volatile sulphur compounds.
  
  
  CONCLUSIONS
  Our results indicate that β-galactosidase is located on the cell surface of oral bacteria derived from dental plaque and tongue coating, and it plays an important role in producing the malodour underlying physiological oral malodour.
authors: Section of General Dentistry, Department of General Dentistry, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, Japan.
authors: Yosuke
authors: Y
authors: Masuo
authors: Nao
authors: N
authors: Suzuki
authors: Masahiro
authors: M
authors: Yoneda
authors: Toru
authors: T
authors: Naito
authors: Takao
authors: T
authors: Hirofuji
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D005260:Female; D006209:Halitosis / Q000201:enzymology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000201:enzymology* / Q000382:microbiology; D012463:Saliva / Q000201:enzymology*; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D001616:beta-Galactosidase