Salivary peroxidase

Takahama, U., Hirota, S., Nishioka, T., and Yoshitama, K., Oxidation of quercetin by salivary components 1. Salivary peroxidase-dependent oxidation of quercetin and characterization of the oxidation products, Food Set Technol. Res., 8, 148, 2002. 

Mammalian peroxidases. Mammalian peroxidases [19] make up a separate peroxidase superfamily (not homologous to any of the enzymes in the previous section). They include proteins used for defence, such as myeloperoxidase [33], lactoperoxidase [34], salivary peroxidase [35] and eosinophil peroxidase [36], as well as those used for biosynthesis, such as thyroid peroxidase [37]. All these enzymes can oxidise halides and pseudohalides in vitro, the main difference being in the redox potential of compound I [38],... 

Exhalation of HCN and of CO2 from oxidative metabohsm (Boxer and Rickards, 1952 Okoh, 1983). Traces of HCN can be detected in expired air of normal humans, but this is not correlated with blood CN. Most HCN in normal breath is derived from the oxidation of SCN by salivary peroxidase in the oropharyx (Lunquist et al., 1988). 

CcP = Cytochrome c Peroxidase BCCP = Bacterial Cytochrome c Peroxidases APX = Soybean or pea or Tobacco Ascorbate Peroxidase MNP = Manganese Peroxidase LIP = Lignin Peroxidase EPO = Eosinophil Peroxidase LPO = Lactoperoxidase MPO = Myeloperoxidase TPO = Thyroid Peroxidase ARP = Arthomyces Ramos us Peroxidase SPO = Salivary Peroxidase PGHsynthase = Prostaglandin Hsynthase KatG = Catalase-peroxidase EPR = Electron Paramagnetic Resonance RR = Resonance Raman BHA = Benzhydroxamic Acid FA = Ferulic Acid DBNBS = 3,5-dibromo-4-nitrosobenzenesulfonic acid ABTS = 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) MNPr = Methylnitrosopropane INH = Isoniazid. 

In saliva, in the presence of hydrogen peroxide, salivary peroxidase oxidizes salivary thiocyanate to hypothiocyanate ... 

Bacon, J.R. and Rhodes, M.J.C., Development of a competition assay for the evaluation of binding of human parotid salivary proteins to dietary complex phenols and tannins using a peroxidase-labeled tannin, J. Agric. Food Chem., 46, 5083, 1998. 

Unquenched endogenous alkaline phosphatase activity may be seen in leucocytes, kidney, liver, bone, ovary bladder, salivary glands, placenta and gastro-intestinal tissue. Add levamisole to the alkaline phosphatase chromogen reagent or use another enzyme label such as horseradish peroxidase. Intestinal alkaline phosphatase is not quenched by the addition of levamisole. Pretreat the tissue with 0.03 N HCI. 115-121... 

In general, kits for the measurement of estradiol in sahva are not commercially available. However, Tamate and coworkers have reported the use of a direct enzyme immunoassay that shows promise for the measurement of salivary estradiol. This assay uses monoclonal anti-estradiol-coated microtiter plates and an estradiol-peroxidase conjugate, No extraction is required. These authors reported a sahvary estradiol peak of 15 to 31 pmol/L in the preovulatory phase and from 9 to 33 pmol/L in the midluteal phase. Lu and co-workers have described a double-antibody RIA using I-labeled estradiol conjugate for the determination of salivary estradiol. ... 

The mere presence of peroxidase, H2O2, and iodide are not necessarily sufficient to ensure formation of I2. Tissues must be capable of concentrating iodide at a sufficient threshold such that the iodide anion can itself compete for binding to the enzyme-bound hypoiodous acid intermediate to yield I2. Currently no evidence exists outside of thyroid and mammary tissue to support the formation of iodinated by-products, although both the salivary gland and ovaries concentrate iodide and express a peroxidase. 

To overcome the defence mechanisms of the host, for example, salivary lysozyme, transferrin, the peroxidase system and salivary antibodies. 

N. M. Alexander, Iodide peroxidase in rat thyroid and salivary glands and its inhibition by antithyroid compounds,/. Biol. Chem. 234, 1530-1533 (1959). 

The other is a soluble enzyme system found in both thyroid and salivary glands 269-272). From the fact that this enzyme system requires H,0, it is presumed to be a peroxidase. The soluble enzyme system can function anaerobically and it iodinates free tyrosine to a mixture of mono- and diodotyrosine. Considerable evidence exists that the enz)rme requires Cu++ for activity, but all workers have not been able to demonstrate this (272). 

---