Effects of Molybdenum, Copper and Iron on Some Enzymes in Neurospora crassa

Abstract

Neurospora crassa was grown at deficient, optimum, and toxic levels of the 3 metals, following which enzyme assays were done on the extracts from the mycelial felts. The enzymes assayed were catalase, peroxidase, DPNH and TPNH oxidases, cytochrome c oxidase, DPN-cytochrome c reductase, nitrate reductase, nitrite reductase, and alkaline and acid phosphatases. Cytochrome c oxidase content was increased by the addition of Cu, decreased by the addition of Mo; the reverse relationship was observed with nitrate reductase. TPNH diaphorase and acid phosphatase were depressed by Cu and Mo respectively. Nitrate reductase was increased by high concentrations of Fe, nitrite reductase was depressed. Mo inhibited acid phosphatase competitively in vitro, but the inhibition was overcome by the addition of Cu. It appears from these experiments that nutrient antagonisms may be related to their effect on certain enzymes.