Stem-Volmer iodide-quenching constant

The Stem-Volmer plots of the fluorescence quenching of the aminoteiminal residue in dermenkephalin and [L-Met ] deimenkephalin by iodide ai e shown in Fig. 5.13. Fluorescence of Tyr in (L-Met ] DREK and that of free L-tyrosine are quenched identically by iodide (Ksv = 19.817 0.025 and 19.298 0.030 M for L-tyrosine and [L-Met ] DREK), respectively (Fig. 5.13a and b). Since iodide quenches tyrosine residue fluorescence within a spatial proximity, the similar values found for Ksv indicates the absence of any matrix siuTounding the tyrosyl side chain. By contrast, the dynamic constant is lower for DREK (Ksv = 13.37 0.02 M (Fig. 5.13c.). 

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