Thermocryptoxanthins: novel intermediates in the carotenoid biosynthetic pathway of Thermus thermophilus
Various thermozeaxanthins are the end products of the carotenoid biosynthetic pathway of the thermophilic eubacterium Thermus thermophilus. These compounds are zeaxanthin glucoside esters. Carotenoid analysis and inhibitory studies led to the identification of most of the intermediates of the pathway: beta-carotene, beta-cryptoxanthin, zeaxanthin, and several new carotenoids. The intermediates, identified by various spectroscopic methods as beta-cryptoxanthin glucoside esters carrying fatty acid moieties of different chain lengths, were designated as thermocryptoxanthins. The use of the inhibitors diphenylamine and 2-(4-chlorophenylthio)-triethylamine-HCl resulted in the accumulation of the intermediates phytoene, lycopene, and gamma-carotene derivatives, which normally are present in amounts below the detection limit. The levels of non-esterified glycosides were extremely low. The results presented were used to establish the complete carotenoid biosynthetic pathway of T. thermophilus.
Yokoyama
A
Marine Biotechnology Institute, Shimizu, Shizuoka 424, Japan
Shizuri
Y
Hoshino
T
Sandmann
G