Stabilization and competitive inhibition of beta-carotene 15,15'-dioxygenase by carotenoids.

Carotenoids stabilize beta-carotene 15,15'-dioxygenase (CDO) during the isolation of the enzyme from the rabbit small intestinal mucosa using a thiol protector and protease inhibitors and in the course of the enzyme purification. The inhibition of CDO by lycopene, lutein and astaxanthin is competitive. Carotenoids partly protect CDO from the action of both iodacetate and trypsin due to enzyme-pseudosubstrate interaction.