Polyisoprenoid alcohols consisting of 9 or more isoprene units are present in all living cells. They can be fully unsaturated (polyprenols) or alpha-saturated (dolichol). Dolichol forms may have additional saturation at or near the omega-end. Some species contain ony dolichol or only polyprenols while others have nearly equal amounts of both types. Some polyisoprenoid alcohols consist entirely of trans isoprene units but most, including dolichol, contain both trans and cis units. Considerable advances in lipid methodology have occurred since the first review of polyisoprenoid alcohols by Hemming in 1974. For example, direct analysis of both dolichol and Dol-P by HPLC has replaced earlier methods which were often both insensitive and inaccurate. The availability of radiolabeled dolichol and polyprenols has facilitated studies concerning the metabolism and distribution of these compounds. Those studies suggest that only a small portion of the dolichol present in cells is likely to be involved in glycosylation. Polyisoprenoid alcohols are usually present at a family of homologues where each differs in size by one isoprene unit. Little or no size related specificity has been observed for any reaction involving dolichol or polyisoprenol intermediates. The overall length of polyisoprenoid alcohols may, however, affect the manner in which these compounds influence the physical and biochemical properties of membranes. Studies on the biosynthetic pathway leading from cis, trans Pol-PP by phosphatase action. The formation of the dolichol backbone from a polyprenol requires the action of an additional enzyme, an alpha-saturase. This enzyme does not always act at the level of a single common substrate, since Pol-PP, Pol-P, and polyprenol all appear to be utilized as substrates. The major product of the de novo pathway differs among different species. Dol-P would appear to be the most energy efficient end-product since it can participate directly in glycoprotein formation. Most often, however, Dol-P is not the major product of metabolic labeling experiments. In some cases, dolichol is formed so that rephosphorylation is required to provide Dol-P for participation in glycoprotein formation. The kinase responsible for this phosphorylation appears to bypass the considerable stores of dolichol present in tissues (i.e. sea urchin eggs) in favor of dolichol derived directly from de novo synthesis. Although HMGR is a major regulatory component of the pathway leading to polyisoprenoid alcohols and cholesterol, control is most often not co-ordinated.(ABSTRACT TRUNCATED AT 400 WORDS)

植物聚戊烯醇是一类异戊烯基结构聚合体的类脂化合物,与人体内多萜醇具有相似的结构特征和生理活性,而多萜醇是糖基与蛋白质生物合成的关键载体.本文重点介绍植物聚戊烯醇的结构类型、HPLC分析、结构鉴定方法和光谱特征、药理和临床应用.针对我国银杏叶加工存在的问题,提出要重点研究银杏叶聚戊烯醇新的有效活性成分,促进银各叶聚戊烯醇作为保健品和药物的开发.

In many plants belonging to angiosperms and gymnosperms the accumulation in leaves of long chain polyprenols and polyprenyl esters during growth in natural habitats depends on the light intensity. The amount of polyprenols in leaves is also positively correlated with the thickness of the leaf blade (SLA, specific leaf area). The polyprenol content of leaves shows seasonal changes with a maximum in autumn and a minimum in early summer with the difference between poorly and well illuminated plants persisting throughout the vegetation season.