Mammalian salivary proteins

The specificity of the interaction of (+)-catechin with poly(L-proline) is not surprising in view of the biological function of polymers of (+)-catechin and (-)-epicatechin. The presence of these polymers in certain plants makes them an unattractive food source for animals. A molecular basis for this protective action may lie in the ability of polymers of (+)-catechin and (-)-epicatechin to interact strongly with mammalian salivary proteins that have an unusually high content of the L-prolyl residue (10,22). ACKNOWLEDGMENTS... 

Table 3.1 Odourant Binding Proteins N-terminai sequences of various mammalian urinary and nasal lipocalyins — correspondence/homology with pig salivary protein, pig-SAL (Id <60%) (from Pelosi, 1998).

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],... 

Many foods obtained from plants contain tannins. These are phenolic compounds that bind proteins, such as mammalian enzymes. It has been shown in vitro that tannic acid significantly reduces the lubricating qualities of human saliva both by decreasing its viscosity and increasing friction [55], This effect depends on the presence of salivary PRPs, which have a high affinity for tannins [56], It has been shown that the introduction of tannins into the diet can stimulate the production of PRPs in the saliva of rats [57], PRPs are a major component of salivary pellicle, and thus it would not be surprising to find that dietary tannins affect the viscosity of pellicle. 

Most proteins found in membranes of mammalian cells are glycosylated. This holds, in particular, for the mucins which are expressed by most types of epithelial cells, e.g. in the salivary gland, hreast, liver, pancreas etc The glycans of glycoproteins not only influence physicochemical properties of these macromolecules and protect the proteins from enzymatic degradation, but also play key functions in processes such as cell adhesion, cell differentiation and cell recognition. 

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