ABSTRACT
Plants produce a greater array of structurally diverse isoprenoids than other organisms, and these are conveniently divided into classes of primary and secondary metabolites. Combined with the pulse labeling experiments and enzyme activity measurements, these studies suggest that squalene synthase is a major control point for the regulation of sterol biosynthesis in plants. The topic of plant isoprenoids encompasses a rich and broad subject area, both of which are derived from a fascination in the diversity of isoprenoids found in nature and intense investigations into their biosynthesis. The results of these two studies are not consistent with the traditional view of isoprenoid metabolism occurring in a homogeneous environment with intermediates mixing freely and accessible to successive or competing enzymes. Instead, the results are more consistent with arrays of isozymes dedicated to the production of specific classes of isoprenoids, with each array regulated independently.
