Borate inhibits activation of inactive dinitrogenase reductase from Rhodospirillum rubrum.

Borate and aminophenylboronic acid were tested as inhibitors of activation of inactive dinitrogenase reductase from Rhodospirillum rubrum. Inhibition was specific for activation because activity of the active form of the enzyme was not inhibited. Inhibition showed the pH-dependence expected if borate inhibits by binding to cis-hydroxy groups of the modifying group found on the inactive enzyme.