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. 1999 Feb 16;96(4):1193–1200. doi: 10.1073/pnas.96.4.1193

Figure 3.

Figure 3

Time course of two-photon photolysis of Bhc-glu (9) at 740 nm (average power 530 mW exiting the cuvet, 172 fs pulse width), compared with breakdown of l-glutamic acid α-(3,4-dimethoxy-6-nitrobenzyl) ester (DMNB-glu, 2) with or without irradiation. ●, Percentage of Bhc-glu remaining from an initial concentration of 100 μM. Solid line, least-squares curve fit to a simple decaying exponential, which gave a time constant of 38 min. The initial rate of this photolysis run, combined with Eq. 3, gave a value of δu2 = 0.85 GM. The mean ± SD of 4 runs was 0.95 ± 0.21 GM. □, Percentage of DMNB-glu remaining under the same conditions. Dashed line, a decaying exponential of time constant 19.8 h, which had been separately measured over much longer times for the breakdown of DMNB-glu in the dark in 100 mM KMops, pH 7.2. Thus the pulsed IR laser beam does not detectably increase the rate of DMNB-glu breakdown.