[Thermal inactivation and storage behavior of technologically important enzymes. III. Effect of reagents added to peroxidase and lipoxygenase].

The influence of milieu factors on the thermal inactivation of peroxidase and lipoxigenase was investigated. Cationogenic, anionogenic, non-ionogenic and amphoteric tensides were more or less effective in inactivating horseradish peroxidase. Most effective in this respect were lecithine and monoglyceride, both capable of swelling in water. In presence of lecithine, peroxidase was inactivated already at 0 degrees C and pH 4.0. Linoleic acid was more efficient in an oxygen stream than in presence of nitrogen, in a stream of nitrogen its influence was comparable to oleic acid. This suggests an additional effect by lipid peroxides which are formed of linoleic acid under the heating process. Tensides prevented the regeneration of the heated peroxidase. In the case of lipoxigenase, the authors investigated the influence of lecithine and various fatty acids on the thermal inactivation at 60 degrees and pH 7.0. Lecithine accelerated the inactivation less distinctly than with peroxidase. The accelerated the inactivation less distinctly than with peroxidase. The accelerating effect of the fatty acids decreased in the order oleic acid, linoleic acid, palmitic acid, myristic acid and stearic acid.