Search

1. Initial velocity studies on β-cyclopiazonate oxidocyclase in the presence of the competitive inhibitor, 3-acetyl-5-scatyl-tetramic acid, indicates that this enzyme catalyzes the oxidocyclization of β-cyclopiazonic acid by a Ping-Pong-Bi-Bi mechanism. 2. It was possible to reduce the flavin coenzyme to the 3,4-dihydroflavin by consecutive cycles of reduction with BH4- and reoxidation by atmospheric oxygen. 8. The BH4-reduced enzyme shows a similar affinity for indole derivatives as does the native flavoquinone enzyme, but is inactive. β-Cyclopiazonic acid binds to the enzyme in a simple equilibrium, and the reduction of the 3,4-dihydroflavin to the 1,3,4,5.tetrahydroflavin or a conversion to 1,5-dihydroflavin does not proceed. 4. Partial reactivation of the enzyme by the photocatalyzed oxidation of the 3,4-dihydroflavin to the flavoquinone form was observed [ABSTRACT FROM AUTHOR]