Astaxanthin accumulation in Haematococcus requires a cytochrome P450 hydroxylase and an active synthesis of fatty acids

Astaxanthin accumulation by green microalgae is a natural phenomenon known as red snows and blood rains. The fact that astaxanthin synthesis requires oxygen, NADPH and Fe2+ led Cunningham and Gantt [Annu, Rev. Plant Physiol, Plant Mel. Biol, 49 (1998) 557-583] to propose that a cytochrome P450-depen dent enzyme might be involved in the transformation of beta -carotene to as taxanthin. In Haematococcus only esterified astaxanthin molecules accumulat e, but it is not determined whether a fatty acid synthesis should occur sim ultaneously to allow pigment accumulation. The aim of this contribution was to answer these two questions using specific inhibitors of beta -carotene (norflurazon) and fatty acid (cerulenin) synthesis, and of cytochrome P450 enzyme activity (ellipticine), (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.