AGMATINE IMINOHYDROLASE IN MAIZE

Agmatine iminohydrolase, which converts agmatine to N-carbamylputrescine and ammonia, was found in extracts of the leaves and seed of maize, and in sunflower seedlings. The energy of activation of the maize leaf enzyme was 19·0 kcal/mole and the energy of activation for the denaturation of the enzyme was 27·8 kcal/mole. The optimum pH lay in the range 6·5-7·5. The enzyme was inhibited by N,N′diguanidinobutane and p-chloromercuribenzoate, and it was highly substrate specific. Potassium-deficient maize leaves were found to possess about thirty times more putrescine than normal maize leaves after 35 days' growth. However, at this age no significant effect of potassium nutrition on agmatine iminohydrolase activity could be demonstrated. © 1969.