CHAPTER
1 1
Terpenoids: Metabolism *
W. SANDERMANN
Federal Research Station for Forestry and Forest Products,
Reinbek/Hamburg, Germany
I. The "Isoprene Rule" and Chemism of Terpenoid Biosynthesis .
.
.
591
II. Ring Closures and Rearrangements
597
III. Biochemical Oxidations and Hydrogenations
602
IV. Chemotaxonomy
614
References
627
I. The "Isoprene Rule" and Chemism of Terpenoid Biosynthesis
The isoprene hypothesis, formulated by Wallach (I) and strongly
promoted by Ruzicka and co-workers (2, 3), states that terpenes and
terpenoids are synthesized in nature from isoprene and isopentane units,
respectively. The most diverse linkages were proposed for these units.
The chemistry of terpenoid biogenesis was advanced, above all, through
work on the metabolism of cholesterol. Reference is therefore made to
Chapter 3 in this volume, as well as to comprehensive discussions (2-9).
Until quite recently, the following acids were recognized as experimentally proved precursors in sterol biogenesis: acetic acid, leucine and
valeric acid, β,β-dimethylacrylic acid (DMA), /?-methylglutaconic acid,
ß-hydroxy-ß-methylglutaric acid (HMG), ß-hydroxyisovaleric acid, and
mevaldic acid (MVALD) (see references 6 and 7, and Chapter 3 in this
volume). The discovery of mevalonic acid by Folkers and co-workers
(6, 8) resulted in the first substantial progress. Through the investigations of the groups headed by Bloch et al. (6) it became certain that
mevalonic acid (VI) was, up to this point, the most important isoprenoid
unit. The aforementioned acids proved to be less effective precursors than
mevalonic acid. Further interesting investigations by Bloch's and Lynen's
groups then yielded proof that the "active isoprene," i.e., the real C 5
unit of all terpenes and terpenoids, is not mevalonic acid itself, but the
isopentenyl pyrophosphate (IX) derived therefrom through phosphorylation and decarboxylation (6, 9-12). In view of the new data, a comprehensive scheme for the biogenesis of terpenes and terpenoids can
be formulated (Fig. 1), based essentially on the work of Lynen (11-13).
From this scheme it can be seen that the same precursor, namely
* Translated from the German by Dr. Herbert S. Heineman, University of
Pittsburgh School of Medicine.
591
1 1
Terpenoids: Metabolism *
W. SANDERMANN
Federal Research Station for Forestry and Forest Products,
Reinbek/Hamburg, Germany
I. The "Isoprene Rule" and Chemism of Terpenoid Biosynthesis .
.
.
591
II. Ring Closures and Rearrangements
597
III. Biochemical Oxidations and Hydrogenations
602
IV. Chemotaxonomy
614
References
627
I. The "Isoprene Rule" and Chemism of Terpenoid Biosynthesis
The isoprene hypothesis, formulated by Wallach (I) and strongly
promoted by Ruzicka and co-workers (2, 3), states that terpenes and
terpenoids are synthesized in nature from isoprene and isopentane units,
respectively. The most diverse linkages were proposed for these units.
The chemistry of terpenoid biogenesis was advanced, above all, through
work on the metabolism of cholesterol. Reference is therefore made to
Chapter 3 in this volume, as well as to comprehensive discussions (2-9).
Until quite recently, the following acids were recognized as experimentally proved precursors in sterol biogenesis: acetic acid, leucine and
valeric acid, β,β-dimethylacrylic acid (DMA), /?-methylglutaconic acid,
ß-hydroxy-ß-methylglutaric acid (HMG), ß-hydroxyisovaleric acid, and
mevaldic acid (MVALD) (see references 6 and 7, and Chapter 3 in this
volume). The discovery of mevalonic acid by Folkers and co-workers
(6, 8) resulted in the first substantial progress. Through the investigations of the groups headed by Bloch et al. (6) it became certain that
mevalonic acid (VI) was, up to this point, the most important isoprenoid
unit. The aforementioned acids proved to be less effective precursors than
mevalonic acid. Further interesting investigations by Bloch's and Lynen's
groups then yielded proof that the "active isoprene," i.e., the real C 5
unit of all terpenes and terpenoids, is not mevalonic acid itself, but the
isopentenyl pyrophosphate (IX) derived therefrom through phosphorylation and decarboxylation (6, 9-12). In view of the new data, a comprehensive scheme for the biogenesis of terpenes and terpenoids can
be formulated (Fig. 1), based essentially on the work of Lynen (11-13).
From this scheme it can be seen that the same precursor, namely
* Translated from the German by Dr. Herbert S. Heineman, University of
Pittsburgh School of Medicine.
591