ABSTRACT
The major prenyllipid classes of higher plants and algae are the sterols, carotenoids, chlorophylls, prenylquinones, and the prenols, all of which are regular plant constituents. A typical feature of the plant prenyllipids group is the fact that they represent regular lipid components of green plants which often have particular functions in the cellular biomembranes. This chapter provides some basic general information on the biosynthesis, localization, and physiological function of individual plant prenyllipids with special emphasis on carotenoids and chlorophylls, as well as on mitochondrial and plastidic prenylquinones. The porphyrin ring of protochlorophyllide (PChlide) is formed via Mg-protoporphyrin IX, which accumulates in dark-grown seedlings and becomes esterified in higher plants with phytol to yield the chlorophyll precursor protochlorophyll (PChl). The prenylalcohol found in the mature chlorophylls a and b is the diterpene phytol. Chloroplasts seem to possess the capacity of mevalonate formation from applied acetate. Isolated chloroplasts were found to exhibit some activity of the key enzyme hydroxymethylglutaryl (HMG)-coenzyme (CoA) reductase.
