Elemental Quantification for Fingerprinting Enzymes

3 Elemental Quant ation for Fingerprinting Enzymes Table 13.1 shows elemental quantification for a range of biomolecules (three enzymes and one peptide) analyzed as either a powder or a soluble cast film. The use of 0/C ratios 

TABLE 13.1 Elemental Composition and Ratios for a Selection of Biomolecules 

For example, in 2008, Ivnitski et al. used the N/C ratio to confirm entrapment of GOx in a silica-CNT composite obtained through lysozyme-catalyzed synthesis of silica on a Toray carbon paper electrode [26]. For samples containing both GOx and lysozyme, the N/C ratio of 0.11 was very close to that of GOx alone, indicating that the majority of enzyme detected by XPS is GOx. By comparison, the ratio in a GOx-free control was much larger (0.24), as would be expected for lysozyme alone. 

FIGURE 13 High-resolution C Is spectrum for (a) lysozyme, (b) glucose oxidase, (c) composite curve fitted conventionally, and (d) composite curve fitted by model photopeaks. 

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