Effect of glucose on the superoxide dismutase production in fungal strain Humicola lutea.

The effect of glucose on superoxide dismutase (SOD) activity produced in Humicola lutea 110 was determined. The relatively high glucose concentration in the medium did not repress SOD levels in the cells. Glycerol, a nonfermentable carbon source, caused a slight stimulation of SOD synthesis. Furthermore, the specific rates of enzyme production in the medium with different glucose concentration showed an insignificant difference. Cyclic AMP had no effect on SOD levels. The shift in metabolism as glucose was depleted resulted in an increase in the rate of synthesis of both isocitric dehydrogenase and SOD. Pentachlorophenol and paraquat, which cause the production of superoxide radicals, caused an increase in SOD activity. These results led us to conclude that it is superoxide ion rather than glucose that is controlling SOD levels.