Title

Kinetics and mechanism of substitution reactions between myoglobin and activated self-assembled monolayers investigated using surface plasmon resonance

Document Type

Journal Article

Publication Date

10-15-2002

Journal

Langmuir

Volume

18

Issue

21

DOI

10.1021/la025767e

Abstract

The rate of the reaction between solution-phase myoglobin and SAMs fabricated from w-X-hexadecylthiomethylbenzenes where X was a mesylate, chloride, or bromide was investigated using surface plasmon resonance (spr). The data were fit to a model in which nonspecific adsorption competes with a second-order substitution reaction between myoglobin and the surface species. The second-order reaction rate constants obtained from the regression analysis were 440 ± 140 M-1s-1 for the bromide, 56 ± 10 M-1s-1 for the mesylate, and 38 ± 12 M-1s-1 for the chloride. The experimental rate law fit to the data and the increase in rate with decreased basicity of the leaving group were consistent with an SN2 mechanism.

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