COMPARATIVE THERMAL STABILITY OF PEROXIDASE ISOZYMES FROM TWO FLAX GENOTROPHS

Abstract

The thermal stability of peroxidase isozymes was examined in vitro in Linum usitatissimum L. Extracts of main stem tissues of the L and S genotrophs produced by Durrant were heat treated over a range of temperatures and times. Isozymes in treated extracts were separated electrophoretically, and peak areas for the four main anionic isozymes, together with their relative mobilities (Rms), were recorded. Peak areas supplied estimates of relative activities. Short duration treatments at 60° and 70 °C demonstrated differences in thermal stability between isozymes and produced changes in Rm. With prolonged treatment at 40 °C, the thermal stability of one isozyme differed from those of the other three. This isozyme was known to have a higher molecular weight than the others. In addition, prolonged treatment at 40 °C demonstrated increased thermal stability of the three lower molecular weight isozymes of genotroph S compared to those of L.