The isoprenoids, cholesterol and rubber, are known to arise from mevalonic (3,5-dihydroxy-3-methylvaleric) acid (5, 7). The same is true of carotenes (1, 6). Thus it has been found in this laboratory that mlevalonic acid is rapidly incorporated into carotenes and related compounds in the tonmato fruit (6). The hydrocarbon fraction of tomatoes previously incubated with 2-C'4-mevalonate contains ...

The effects of diphenylamine, dimethyl sulfoxide, streptomycin, AMO-1618, and beta-ionone on the carotene composition of a wild-type and three mutant strains of Phycomyces blakesleeanus have been examined. Diphenylamine increased the phytoene and phytofluene concentrations of all strains while reducing the levels of the color carotenes. Dimethyl sulfoxide reduced the concentration of both cycli...

Dietary intake of vitamin A (VA) and carotenes has shown beneficial effects for decreasing the risk of some types of cancer, but findings on the risk of primary liver cancer (PLC) are inconsistent. This case-control study explored the associations between the dietary intake of VA and carotenes and the risk of PLC. We recruited 644 incident PLC patients (diagnosed within one month of each other)...

A review is given of the development of the industrial manufacture of carotenoids and vitamin A by isolation and by synthesis. Special emphasis is placed on the use of carotenoids as a preferred class of colouring matters for food and feed. INTRODUCTION A review of the industrial manufacture of carotenoids and vitamin A may be separated into four areas: First the area of isolation and the struc...

Data are presented in this paper which establish many of the reactions involved in the biosynthesis of carotenes. Studies have shown that all of the enzymes required for the synthesis of acyclic and cyclic carotenes from mevalonic acid are present in plastids of tomato fruits. Thus, it has been demonstrated that a soluble extract of an acetone powder of tomato fruits converts mevalonic acid to ...

The pathway of carotene biosynthesis from isopentenyl pyrophosphate in tomato fruit plastids has been established, except for minor details, through the conversion of radioactive sub— strates and intermediates to acyclic and cyclic carotenes in cell—free systems. After the pathway of carotene biosynthesis was established attention was turned to the isola— tion and purification of enzymes of car...

The ratio of cis and all-trans lycopene (LYC) in human and animal tissues exceeds that in foods. The basis for this difference remains unknown, although differences in their stability, transport, and metabolism have been suggested. Here, we systematically compared the digestive stability, efficiency of micellarization, and uptake and intracellular stability of cis and all-trans isomers of LYC a...