| 16289439 |
Zhao G, Chasteen ND: Oxidation of Good's buffers by hydrogen peroxide. Anal Biochem. 2006 Feb 15;349(2):262-7. Epub 2005 Oct 25.
Good's zwitterionic buffers are widely used in biological and biochemical research in which hydrogen peroxide is a solution component. This study was undertaken to determine whether Good's buffers exhibit reactivity toward H (2) O (2). It is found that H (2) O (2) oxidizes both morpholine ring-containing buffers (e.g., Mops, Mes) and piperazine ring-containing zwitterionic buffers (e.g., Pipes, Hepes, and Epps) to produce their corresponding N-oxide forms. The percentage of oxidized buffer increases as the concentration of H (2) O (2) increases. However, the rate of oxidation is relatively slow. For example, no oxidized Mops was detected 2h after adding 0.1M H (2) O (2) to 0.1M Mops (pH 7.0), and only 5.7% was oxidized after 24h exposure to H (2) O (2). Thus, although all of these buffers can be oxidized by H (2) O (2), their slow reaction does not significantly perturb levels of H (2) O (2) in the time frame and at the concentrations of most biochemical studies. Therefore, the previously reported rapid loss of H (2) O (2) produced from the ferroxidase reaction of ferritin is unlikely due to reaction of H (2) O (2) with buffer, a conclusion supported by the fact that H (2) O (2) is also lost rapidly when the solution pH of the ferroxidase reaction is controlled by a pH stat apparatus in the absence of buffer. |
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