EFFECT OF TEMPERATURE ON CATALASE ACTIVITY

A search of the literature for an enzyme already quite well known which might be involved directly or indirectly in photosynthetic reactions suggested catalase. Catalase occurs in chloroplasts (Neish, Krossing), its activity in light grown corn seedlings is greater in green ones than in albino or in yellow ones (Eyster, 1950) and it is heat sensitive at much below the boiling point of water and at a tem-perature which it was thought might possibly explain the maximum temperature for photosynthesis. Leaves exposed for one minute at 55 ° C. and above lost the ability both to form chlorophyll and to transform sugar into starch (Eyster, 1949). It was there-fore of interest to study the thermal stability of catalase, and to determine the critical temperature at and above which destruction of catalase in corn seedling leaves occurs. METHODS AND MATERIALS Green and etiolated corn seedlings were grown and were subjected to a series of temperatures by means of a water bath. The temperatures employed wer