Differentiation of myeloperoxidase and glandular peroxidase in biological fluids: application to human saliva.
A modification of the assay system for peroxidase activity in human mixed saliva using 2,2'-azinobis-(-ethylbenzthiazoline-6-sulphonic acid) (ABTS) as the substrate is reported. The modifications permit differentiation between glandular peroxidase (SPX) and myeloperoxidase (MPX) activity. In addition, factors endogenous to saliva such as thiocyanate did not adversely affect the modified assay system. The basic peroxidase assay utilized 1.0 mM ABTS and 0.1 mM H2O2 in 0.1 M sodium acetate, pH 4.7. The addition of 100 mM NaCl to the assay inhibited 90% of the activity of purified MPX but only 40% of the SPX activity in parotid saliva presumed to be free of MPX. Addition of Cl- to the assay had varied effects on the mixed saliva SPX activity (44-68% inhibition), suggesting that MPX is present in varying amounts in mixed saliva. Assay of mixed saliva from patients with different states of periodontal health indicated that the amount of Cl- inhibition is dependent on amount of inflammation and thus amount of MPX present. The results suggest that the modified assay yields a reliable estimate of relative SPX activity in mixed saliva.
Venezie
R D
RD
Dental Research Center, School of Dentistry, University of North Carolina, Chapel Hill 27599-7455.
Jenzano
J W
JW
Lundblad
R L
RL
D052160:Benzothiazoles; D006801:Humans; D007249:Inflammation / Q000201:enzymology; D009195:Peroxidase / Q000032:analysis*; D012463:Saliva / Q000201:enzymology*; D012965:Sodium Chloride; D013379:Substrate Specificity; D013451:Sulfonic Acids
D052160:Benzothiazoles; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D012965:Sodium Chloride; D009195:Peroxidase