ABSTRACT
Polyprenoid alcohols are linear polymers of isoprene, consisting of 622 units with a terminal primary alcohol group. In the past, polyprenoid alcohols have been referred to collectively as polyprenols, regardless of whether the terminal isoprene unit (α-isoprene unit) is saturated or unsaturated. Among the polyisoprenoid alcohols, compounds which contain a saturated α-isoprene unit (Figure 1) are usually referred to as dolichols. The term dolichol (from the Greek dolichos meaning long) was first applied to a mixture of polyisoprenoid alcohols isolated from pig liver. These compounds are normally found in animal tissue, but have also been found in plants. At present, the term polyprenols is restricted to α-unsaturated compounds in order to distinguish them from dolichols. The generalized structure of polyisoprenoid alcohols in terms of cis, trans conformation is shown in Table 1 (top). Certain polyprenoid alcohols differ from dolichols, belonging to Family I, since they have more than 2 internal trans isoprene units at the ω-end of the chain (Family II) or they have all the double bonds in the trans configuration (Family III).
