Biosynthesis of carotenoids by Phycomyces blakesleeanus mutants in the presence of nitrogenous heterocyclic compounds
Date of Original Version
Pyridine, imidazole and some of their derivatives stimulate lycopene and γ-carotene synthesis-simultaneously inhibiting β-carotene formation in Phycomyces blakesleeanus Strain C115. Isonicotinoly-hydrazine has a toxic effect on Strains C9 and C115 and 1-methylimidazole on Strain C115 in the concentrations of 1 g/l. Compounds which cause an accumulation of lycopene and γ-carotene usually cause an increase in phytoene synthesis and the disappearance of β-zeacarotene. The effect of succinimide, 4-hydroxypyridine, and isonicotinoylhydrazine on Strain C9 has also been studied. When β-picoline and 2-methylimidazole treated C115 mycelia were washed and resuspended in phosphate buffer at pH 5·6 β-zeacarotene reappeared and β-carotene increased with the simultaneous decrease in lycopene and γ-carotene. The sum of β-carotene, γ-carotene up to 3days of resuspension was almost equal to the total of these at zero time. These results show that the inhibitory action of these compounds is on the enzymes responsible for cyclization of acyclic carotenes. This inhibition varies with the nature of the substituent on the heterocyclic ring and pyridine derivatives having pKa values of 6 ± 1 show the greatest degree of inhibition. © 1973.
Elahi, Manzoor, Clinton O. Chichester, and Kenneth L. Simpson. "Biosynthesis of carotenoids by Phycomyces blakesleeanus mutants in the presence of nitrogenous heterocyclic compounds." Phytochemistry 12, 7 (1973): 1627-1632. doi:10.1016/0031-9422(73)80380-2.