Purification and biosynthesis of cottonseed (Gossypium hirsutum L.) catalase

Enhanced-peroxidatic activity in specific catalase isozymes of tobacco, barley, and maize

Separation of catalase isozymes from leaf extracts of three diverse plant species (Nicotiana sylvestris, Zea mays, Hordeum vulgare L.) revealed a distinct isozyme with enhanced peroxidatic activity (30-, 70-, 28-fold over typical catalase, respectively) which constituted 10 to 20% of the total catalase activity. In maize this isozyme is the product of the Cat3 gene, which is expressed only in mesophyll cells (AS Tsaftaris, AM Bosabalidis, JG Scandalios [1983] Proc Natl Acad Sci USA 80: 4455-4459). A mutation in barley reducing levels of peroxisomal catalase (AC Kendall et al. [1983] Planta 159: 505-511) does not reduce the amount of the isozyme with enhanced peroxidatic activity. Similarly, this isozyme is unaffected in dark-grown barley in spite of a 75% decrease in total catalase activity. These results suggest that this catalase isozyme is under separate genetic control in barley. This may also be the case in tobacco where the catalase isozyme with enhanced peroxidatic activity is an immunologically distinct protein (EA Havir, NA McHale [1989] Plant Physiol 89: 952-957).

Enhanced-peroxidatic activity in specific catalase isozymes of tobacco, barley, and maize

Separation of catalase isozymes from leaf extracts of three diverse plant species (Nicotiana sylvestris, Zea mays, Hordeum vulgare L.) revealed a distinct isozyme with enhanced peroxidatic activity (30-, 70-, 28-fold over typical catalase, respectively) which constituted 10 to 20% of the total catalase activity. In maize this isozyme is the product of the Cat3 gene, which is expressed only in mesophyll cells (AS Tsaftaris, AM Bosabalidis, JG Scandalios [1983] Proc Natl Acad Sci USA 80: 4455-4459). A mutation in barley reducing levels of peroxisomal catalase (AC Kendall et al. [1983] Planta 159: 505-511) does not reduce the amount of the isozyme with enhanced peroxidatic activity. Similarly, this isozyme is unaffected in dark-grown barley in spite of a 75% decrease in total catalase activity. These results suggest that this catalase isozyme is under separate genetic control in barley. This may also be the case in tobacco where the catalase isozyme with enhanced peroxidatic activity is an immunologically distinct protein (EA Havir, NA McHale [1989] Plant Physiol 89: 952-957).

Catalase Synthesis and Turnover during Peroxisome Transition in the Cotyledons of Helianthus annuus L

Based on measurements of total catalase hematin and the degradation constants of catalase hematin, zero order rate constants for the synthesis of catalase were determined during the development of sunflower cotyledons (Helianthus annuus L.). Catalase synthesis reached a sharp maximum of about 400 picomoles hematin per day per cotyledon at day 1.5 during the elaboration of glyoxysomes in the dark. During the transition of glyoxysomes to leaf peroxisomes (greening cotyledons, day 2.5 to 5) catalase synthesis was constant at a level of about 30 to 40 picomoles hematin per day per cotyledon. In the cotyledons of seedlings kept in the dark (day 2.5 to 5) catalase synthesis did not exceed 10 picomoles hematin per day per cotyledon. During the peroxisome transition in the light, total catalase hematin was maintained at a high level, whereas total catalase activity rapidly decreased. In continuous darkness, total catalase hematin decreased considerably from a peak at day 2. The results show that both catalase synthesis and catalase degradation are regulated by light. The turnover characteristics of catalase are in accordance with the concept that glyoxysomes are transformed to leaf peroxisomes as described by the one population model and contradict the two population model and the enzyme synthesis changeover model which both postulate de novo formation of the leaf peroxisome population and degradation of the glyoxysome population.

Regulation of Catalase Activity in Leaves of Nicotiana sylvestris by High CO(2)

The effect of high CO(2) (1% CO(2)/21% O(2)) on the activity of specific forms of catalase (CAT-1, -2, and -3) (EA Havir, NA McHale [1987] Plant Physiol 84: 450-455) in seedling leaves of tobacco (Nicotiana sylvestris, Nicotlana tabacum) was examined. In high CO(2), total catalase activity decreased by 50% in the first 2 days, followed by a more gradual decline in the next 4 days. The loss of total activity resulted primarily from a decrease in CAT-1 catalase. In contrast, the activity of CAT-3 catalase, a form with enhanced peroxidatic activity, increased 3-fold in high CO(2) relative to air controls after 4 days. Short-term exposure to high CO(2) indicated that the 50% loss of total activity occurs in the first 12 hours. Catalase levels increased to normal within 12 hours after seedlings were returned to air. When seedlings were transferred to air after prolonged exposure to high CO(2) (13 days), the levels of CAT-1 catalase were partially restored while CAT-3 remained at its elevated level. Levels of superoxide dismutase activity and those of several peroxisomal enzymes were not affected by high CO(2). Total catalase levels did not decline when seedlings were exposed to atmospheres of 0.04% CO(2)/5% O(2) or 0.04% CO(2)/1% O(2), indicating that regulation of catalase in high CO(2) is not related directly to suppression of photorespiration. Antibodies prepared against CAT-1 catalase from N. tabacum reacted strongly against CAT-1 catalase from both N. sylvestris and N. tabacum but not against CAT-3 catalase from either species. This observation, along with the rapid changes in CAT-1 and the much slower changes in CAT-3 suggest that one form is not directly derived from the other.