## 2 Sources and Composition of Human Saliva: Host and Microbial Contributions
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Assignment** & **Assignment Code** &
\begin{tabular}{c} **Chemical Shift** \\ **(s/ppm)** \\ \end{tabular} & **Coupling Pattern** \\ \hline
3-Methylhistidine-N3(CH3) & 79A & 3.709 & \(s\) \\ \hline Lysine-\(\alpha\)-CH & 80 & 3.718 & \(m\) \\ \hline Leucine-\(\alpha\)-CH & 81 & 3.733 & \(m\) \\ \hline \multicolumn{1}{c}{* Gluconate-C4/C5-CHOH} & 82 & 3.741 & \(m\) \\ \hline Guanidoacetate-CH2 & 83 & 3.760 & \(s\) \\ \hline Alanine-\(\alpha\)-CH/Glycerol-CHOH & 84 & 3.771 & \(m/m\) \\ \hline Ethanolamine-CH2 OH/\(\beta\)-Fucose-C5H & 85 & 3.814 & \(t/m\) \\ \hline \multicolumn{1}{c}{* \(\alpha\)-Fucose-C3H} & 86 & 3.852 & \(m\) \\ \hline Serine-\(\alpha\)-CH & 87 & 3.901 & \(m\) \\ \hline Glycolate-CH2 OH & 88 & 3.929 & \(s\) \\ \hline Tyrosine-\(\alpha\)-CH & 89 & 3.934 & \(m\) \\ \hline Creatine-N-CH2 & 90 & 3.958 & \(s\) \\ \hline Histidine/Phenylalanine-\(\alpha\)-CH & 91 & 3.985 & \(m\) \\ \hline
4-Hydroyphenylpyruvate-CH2 & 92 & 3.996 & \(s\) \\ \hline Tryptophan-\(\alpha\)-CH & 92A & 4.032 & \(dd\) \\ \hline Lactate-CH & 93 & 4.120 & \(q\) \\ \hline
3-D-Hydroxybutyrate-CHOH & 94 & 4.132 & \(m\) \\ \hline \multicolumn{1}{c}{\(\alpha\)-Fucose-C5H} & 95 & 4.198 & \(m\) \\ \hline Threonine-\(\beta\)-CHOH & 95A & 4.234 & \(m\) \\ \hline \multicolumn{1}{c}{\(\alpha\)-Fucose-C1H} & \(\alpha\)-Fuc & 5.209 & \(d\) \\ \hline \multicolumn{1}{c}{\(\alpha\)-Glucose-CH} & \(\alpha\)-Glc & 5.232 & \(d\) \\ \hline Sucrose-C1H & Sucr & 5.414 & \(d\) \\ \hline Allantoin-CH & 96 & 5.392 & \(s\) \\ \hline Senecioate-\(\alpha\)-CH=C\(<\) & 97 & 5.666 & \(s\) \\ \hline Urea-CO-NH2 & 98 & 5.79 & _broad_ \\ \hline Uracil-C2H & 99 & 5.800 & \(d\) \\ \hline Fumarate-CH=CH- & 100 & 6.52 & \(s\) \\ \hline
4-Hydroyphenylacetate aromatic ring-C3H/C5H & 101 & 6.84 & \(d\) \\ \hline \multicolumn{1}{c}{* Protein aromatic amino acid residue(s)} & 102 & 6.85 & _broad_ \\ \hline Tyrosine aromatic ring-C2H/C6H & 103 & 6.880 & \(d\) \\ \hline Histidine imidazole ring-C5H & 104 & 7.071 & \(s\) \\ \hline
4-hydroxyphenylacetate aromatic ring-C2H/C6H & 104A & 7.155 & \(d\) \\ \hline Tyrosine aromatic ring-C3H/C5H & 105 & 7.237 & \(d\) \\ \hline Phenylalanine aromatic Ring-C2H/C6H & 106 & 7.320 & \(m\) \\ \hline Phenylalanine aromatic ring-C4H & 107 & 7.375 & \(m\) \\ \hline Phenylalanine aromatic ring-C3H/C5H & 108 & 7.43 & \(m\) \\ \hline Uracil-C1H & 109 & 7.533 & \(d\) \\ \hline \multicolumn{1}{c}{* Protein aromatic amino acid residue(s)} & 110 & 7.552 & \(m\) \\ \hline Histidine imidazole ring-C2H & 111 & 7.812 & \(s\) \\ \hline
3-Methylhistidine imidazole ring-C2H & 112 & 7.913 & \(s\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(Cont.\)As previously reported [2; 3; 4], these typical spectral profiles provide a wealth of valuable metabolic information concerning the nature and salivary concentrations of an extensive range of biomolecules, both host- and oral microbiome-derived, including many organic acid anions, amino acids (both aliphatic and aromatic), carbohydrates, malodorous amines such as trimethylamine and putrescine, choline and its derivatives, N-acetyl sugars, and N-acetyl amino acids, etc. Also detectable are a number of broad resonances that presumably arise from salivary proteins, most notably those centered at \(\delta\) = 6.85 and 7.55 ppm. These signals are therefore likely to be assignable to protein tyrosine, phenylalanine, tryptophan, and/or histidine residues, and in [20], [PERSON] et al. also found these resonances in both WMS supernatant and parotid saliva samples. In view of this observation, it appears very likely that such macromolecules arise from a host and not a microbial source. Therefore, the intensities of these signals, and hence the concentrations of their assigned biomolecule(s), may potentially be valuable for determining host contributions towards the salivary metabolome. Further experiments to explore this are currently in progress in our laboratories.