Beschreibung
The carotenoids are not only amongst the most widespread of the naturally occurring groups of pigments, but probably also have the most varied functions; witness their known roles in photokinetic responses of plants, in phototropic responses of fish and as vitamin A precursors in mammals and birds. Pigments with such wide distribution and such diverse functions are obviously of great interest to biological scientists with very different specializa tions, especially as it is unlikely that the study of the functions of carotenoids is anywhere near complete. The primary aim of the present work is to discuss the distribution, bio genesis and function of the carotenoids throughout the plant and animal kingdoms in such a way that, because of, rather than in spite of its bio chemical bias, it will be of value to workers interested in all the biological aspects of these pigments. The biochemical approach is considered the most effective because, generally speaking, most progress in the study of carotenoids in living material has been achieved using biochemical techniques, be they applied by zoologists, botanists, entomologists, microbiologists or other specialists; what is even more important is that a consideration of the present position makes it certain that further fundamental progress will also be made along biochemical lines.
Autorenporträt
Inhaltsangabe1. NATURE AND PROPERTIES.- 1.1 Introduction.- 1.2 Nomenclature and structure.- 1.2.1 Carotenoid hydrocarbons.- 1.2.2 Oxygenated carotenoids.- 1.2.3 Retro-carotenoids.- 1.2.4 Seco- and Apocarotenoids.- 1.2.5 Nor-carotenoids.- 1.2.6 Higher carotenoids.- 1.2.7 Stereochemistry.- 1.3 Isolation and purification.- 1.4 Physical properties.- 1.4.1 Absorption spectroscopy.- (a) Localization of absorption maxima.- (b) Shape and intensity of spectra.- (c) Solvent effects.- 1.4.2 Infra-red spectroscopy (i.r.).- 1.4.3 Mass spectrometry (m.s.).- 1.4.4 Nuclear magnetic resonance spectroscopy (n.m.r.).- (a) Proton magnetic resonance spectroscopy (p.m.r.).- (b) Carbon magnetic resonance spectroscopy (C.m.r.).- 1.4.5 Optical rotatory dispersion (o.r.d.) and circular dichroism (c.d.).- 1.4.6 X-ray crystallography.- 1.5 Chemical properties.- 1.5.1 Reactions with acids.- 1.5.2 Reactions with bases.- 1.5.3 Hydride reductions.- 1.5.4 Stereochemistry - absolute configuration.- 1.6 Addendum.- 1.7 References.- 2. BIOSYNTHESIS OF CAROTENOIDS.- 2.1 Introduction.- 2.2 General pathway to lycopene.- 2.2.1 Formation of isopentenyl pyrophosphate.- 2.2.2 Formation of phytoene.- 2.2.3 Stereochemistry of phytoene formation.- 2.2.4 Desaturation of phytoene.- 2.2.5 Nature of enzymes involved in phytoene desaturation.- 2.2.6 Stereochemistry of the desaturation.- 2.3 Further reactions of lycopene.- 2.3.1 Cyclization of lycopene.- (a) Inhibitor and enzyme studies.- (b) Mechanisms.- (c) Formation of C45and C50carotenoids.- (d) Formation of caroten-2-ols.- (e) Formation of aromatic carotenoids.- (f) Carotenoids with cyclopentane rings.- (g) Stereochemistry of cyclization.- 2.3.2 Cyclization of precursors other than lycopene.- 2.3.3 Hydration of lycopene.- 2.3.4 Hydrogenation of lycopene.- 2.3.5 Addition of C5 units to C40 units without cyclization.- 2.4 Insertion of oxygen into carotenoids.- 2.4.1 Hydroxylation.- 2.4.2 Methylation of hydroxyl groups.- 2.4.3 Insertion of carbonyl groups.- 2.4.4 Formation of epoxides.- 2.4.5 Secocarotenoids.- 2.4.6 Carotenoid acids.- 2.5 Acetylenic, allenic and refrocarotenoids.- 2.6 C30 carotenoids.- 2.7 References.- 3. FUNCTIONS OF CAROTENOIDS.- 3.1 Introduction.- 3.2 Photosynthesis.- 3.2.1 Energy transfer.- (a) Light harvesting.- (b) Fluorescence quenching.- 3.2.2 Reaction centre carotenoids.- 3.3 Photoprotection.- 3.3.1 Photosynthetic tissues.- 3.3.2 Non-photosynthetic tissues.- 3.3.3 Mechanism of lethal oxidation.- 3.3.4 Mechanism of photoprotection.- 3.3.5 Protection against ultra-violet radiation.- 3.4 The xanthophyll cycle.- 3.5 Phototropism.- 3.6 Phototaxis.- 3.7 Sporangiophore formation.- 3.8 References.- 4. CAROTENOIDS IN SEED-BEARING PLANTS-PHOTOSYNTHETIC TISSUES.- 4.1 Qualitative distribution.- 4.2 Quantitative distribution.- 4.2.1 Interspecies differences.- 4.2.2 Intraplant variation.- 4.3 Localization.- 4.4 Etiolated seedlings.- 4.5 Mutants.- 4.5.1 Maize.- 4.5.2 Tomato.- 4.5.3 Helianthus.- 4.5.4 Barley.- 4.5.5 Miscellaneous.- 4.6 Synthesis in germinating seedlings.- 4.6.1 Early stages.- 4.6.2 Later stages.- 4.7 Effect of environment on synthesis in leaves.- 4.7.1 Light.- (a) Etiolated seedlings.- (b) Normal seedlings.- 4.7.2 Temperature.- 4.7.3 Nitrogen metabolism.- 4.7.4 Soil nutrients.- 4.7.5 Physico-chemical properties of soil.- 4.7.6 Elevation.- 4.7.7 Hormones.- 4.7.8 Pathogenic agents.- 4.7.9 Herbicides.- 4.7.10 Fungicides and insecticides.- 4.7.11 Antibiotics.- 4.7.12 Osmotic pressure.- 4.8 Biosynthesis.- 4.8.1 Acetyl-CoA formation.- 4.8.2 Formation of mevalonic acid.- 4.8.3 Conversion of mevalonic acid into carotenoids.- 4.8.4 Conclusion.- 4.9 Regulation of synthesis.- 4.10 Metabolism.- 4.10.1 Formation of abscisic acid.- 4.10.2 Senescence.- 4.10.3 Degradation in vivo.- 4.11 Plant tissue cultures.- 4.12 Parasitic and saprophytic plants.- 4.13 Aquatic higher plants.- 4.14 References.- 5. CAROTENOIDS IN HIGHER PLANTS.- 5.1 Reproductive tissues.- 5.1.1 Anthers, pollen and filaments.- (a) Anthers.- (b) Pollen.- (c) Filam
