Model systems for flavoenzyme activity: aromatic stacking in sol-gel matrices

Abstract

Silicate matrices effectively replicate both the isolation and preorganization found in the active sites of flavoenzymes.

References

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12. Synthesized in 75% yield from 2-aminoanthracene and 3-(triethoxysilyl) propyl isocyanate.
13. N-Alkylurea analogs of 2 shows essentially identical quenching behavior as for 2, demonstrating that hydrogen bonding to the urea is not involved in flavin recognition.
14. Solution studies have shown that additional anthracene–flavin interactions have little effect on flavin fluorescence, allowing selective monitoring of the 1 : 1 complex. The large excesses of receptor 2 used should minimize the effect of 2 : 1 receptor flavin binding on the receptor available for the first binding event.
15. The uncertainty presented is the asymptotic standard error. As this system is not in the standard state, the calculated K_a value is for comparison purpose only.
16. N¹⁰-Isobutylflavin 3 was used for these studies due to the low solubility of 1 in EtOH.
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18. At the concentrations of flavin 1 used in these sol-gel experiments, there is no deviation from ideal fluorescence dependence on concentration. This indicates that there are no flavin–flavin interactions occurring, demonstrating site isolation of the flavin species.