= Michael J. Knight
{c}
<Michael J. Knight> is the first author of a 2016 study that reconstructed biological <silicon> transport using purified <proteins>. The investigators placed <diatom> <silicon transporters> in artificial <liposomes>, then measured entry of <silicic acid> with an internal <zinc>-dependent <fluorescence> assay. Applying a <sodium> gradient let them investigate transport outside the many interacting processes of a living <biological cell>.<Direct evidence of the molecular basis for biological silicon transport by Michael J. Knight and others>[Proteoliposome transport assays, Figures 4–5]{ref}
The measured transport saturated as the <silicic acid> concentration increased, with apparent <Michaelis constants> near 20 micromolar for two of the tested <proteins>. For an illustrative saturation law $v/V_{\max}=C/(K_M+C)$ with $K_M=20$ micromolar, increasing $C$ from 20 to 80 micromolar increases the predicted rate from $0.5V_{\max}$ to $0.8V_{\max}$, rather than multiplying it by four. The experiment therefore connects a mineral nutrient with a quantifiable molecular transport process. Its <fluorescence> signal came from an indicator reaction, so calibration and background controls were essential.<Direct evidence of the molecular basis for biological silicon transport by Michael J. Knight and others>[Zinc silicate fluorescence; Proteoliposome transport assays]{ref}
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