Micromethods in single muscle fibers. 1. Determination of catalase and superoxide dismutase

Lawrence Austin*, Helen Arthur, Michael de Niese, Asitha Gurusinghe, Mark S. Baker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Methods have been developed for the measurements of catalase and superoxide dismutase (SOD) in single, isolated muscle fibers. These fibers are also classified according to fiber type. Catalase is determined using a fluorescent method for the measurement of hydrogen peroxide consumed. SOD measurements are carried out using a modification of established techniques whereby the inhibition of oxidation of epinephrine by SOD is assayed fluorometrically. Both enzymes may be determined in submicrogram samples of dried muscle. This approach avoids the complication of the inclusion of nonmuscle tissue with varying enzymatic activities which is frequently experienced when using homogenates of muscle, particularly diseased muscle. In addition, these techniques can be used to determine the inherent variation in SOD and catalase activities within individual fibers of the same fiber type. The Km and Vmax for catalase, deter-mined using homogenates of human muscle, were found to be 12 mm and 1.45 μmol/min/mg dry wt, respectively. Catalase of muscle was inhibited 50% by 2 μm sodium azide. Mn-SOD contributes less than one-fifth of the total SOD activity. Therefore the activity is largely due to the CuZn form of SOD. These methods are applicable to a wide variety of tissues.

Original languageEnglish
Pages (from-to)568-574
Number of pages7
JournalAnalytical Biochemistry
Volume174
Issue number2
DOIs
Publication statusPublished - 1 Nov 1988
Externally publishedYes

Keywords

  • enzymatic control
  • membrane structure
  • muscle biochemistry
  • muscle fibers
  • oxyradicals
  • ultramicrotechniques

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