Preface xv
Part I General Aspects of Nucleotide Metabolism 1
1 Structures of Nucleotide-Related Compounds 3
1.1 Introduction 3
1.2 Nomenclature and Abbreviations of Nucleotide-Related Compounds 3
1.3 Chemical Structures of Nucleotide-Related Compounds 5
1.4 Summary 11
References 11
2 Occurrence of Nucleotides and Related Metabolites in Plants 13
2.1 Purines and Pyrimidines 13
2.2 Pyridine Nucleotides 17
2.3 Concentration of Cytokinins 18
2.4 Alkaloids Derived from Nucleotides 18
2.5 Summary 19
References 19
3 General Aspects of Nucleotide Biosynthesis and Interconversions 21
3.1 Introduction 21
3.2 De Novo Biosynthesis of Ribonucleoside Monophosphates 21
3.3 Interconversion of Nucleoside Monophosphates, Nucleoside Diphosphates, and Triphosphates 23
3.4 Conversion of Nucleoside Diphosphates to Nucleoside Triphosphates 24
3.5 Biosynthesis of Deoxyribonucleotides 29
3.6 Nucleic Acid Biosynthesis 29
3.7 Supply of 5-Phosphoribosyl-1-Pyrophosphate 30
3.8 Supply of Amino Acids for Nucleotide Biosynthesis 33
3.9 Nitrogen Metabolism and Amino Acid Biosynthesis in Plants 33
3.10 Summary 34
References 35
Part II Purine Nucleotide Metabolism 39
4 Purine Nucleotide Biosynthesis De Novo 41
4.1 Introduction 41
4.2 Reactions and Enzymes 43
4.3 Summary 52
References 52
5 Salvage Pathways of Purine Nucleotide Biosynthesis 55
5.1 Introduction 55
5.2 Characteristics of Purine Salvage in Plants 56
5.3 Properties of Purine Phosphoribosyltransferases 59
5.4 Properties of Nucleoside Kinases 62
5.5 Properties of Nucleoside Phosphotransferase 65
5.6 Role of Purine Salvage in Plants 66
5.7 Summary 66
References 66
6 Interconversion of Purine Nucleotides 71
6.1 Introduction 71
6.2 Deamination Reactions 71
6.3 Dephosphorylation Reactions 75
6.4 Glycosidic Bond Cleavage Reactions 76
6.5 In Situ Metabolism of 14C-Labelled Purine Nucleotides 79
6.6 In Situ Metabolism of Purine Nucleosides and Bases 80
6.7 Summary 88
References 89
7 Degradation of Purine Nucleotides 95
7.1 Introduction 95
7.2 (S)-Allantoin Biosynthesis from Xanthine 97
7.3 Catabolism of (S)-Allantoin 101
7.4 Purine Nucleotide Catabolism in Plants 106
7.5 Accumulation and Utilization of Ureides in Plants 107
7.6 Summary 111
References 111
Part III Pyrimidine Nucleotide Metabolism 117
8 Pyrimidine Nucleotide Biosynthesis De Novo 119
8.1 Introduction 119
8.2 Reactions and Enzymes of the De Novo Biosynthesis 121
8.3 Control Mechanism of De Novo Pyrimidine Ribonucleotide Biosynthesis 127
8.4 Biosynthesis of Thymidine Nucleotide 129
8.5 Summary 131
References 131
9 Salvage Pathways of Pyrimidine Nucleotide Biosynthesis 137
9.1 Introduction 137
9.2 Characteristics of Pyrimidine Salvage in Plants 137
9.3 Enzymes of Pyrimidine Salvage 139
9.4 Role of Pyrimidine Salvage in Plants 145
9.5 Summary 146
References 146
10 Interconversion of Pyrimidine Nucleotides 149
10.1 Introduction 149
10.2 Deaminase Reactions 149
10.3 Nucleosidase and Phosphorylase Reactions 152
10.4 In Situ Metabolism of 14C-Labelled Pyrimidines 153
10.5 Summary 159
References 160
11 Degradation of Pyrimidine Nucleotides 165
11.1 Introduction 165
11.2 Enzymes Involved in the Degradation Routes of Pyrimidines 166
11.3 The Metabolic Fate of Uracil and Thymine 168
11.4 Summary 169
References 170
Part IV Physiological Aspects of Nucleotide Metabolism 173
12 Growth and Development 175
12.1 Introduction 175
12.2 Embryo Maturation 175
12.3 Germination 180
12.4 Organogenesis 185
12.5 Breaking Bud Dormancy 186
12.6 Fruit Ripening 186
12.7 Storage Organ Development and Sprouting 186
12.8 Suspension-Cultured Cells 187
12.9 Molecular Studies 189
12.10 Summary 189
References 189
13 Environmental Factors and Nucleotide Metabolism 195
13.1 Introduction 195
13.2 Effect of Phosphate on Nucleotide Metabolism 195
13.3 Effect of Salts on Nucleotide Metabolism 199
13.4 Effect of Water Stress 202
13.5 Effect of Wound Stress 202
13.6 Effect of Iron Deficiency 205
13.7 Effect of Light 206
13.8 Summary 206
References 206
Part V Purine Alkaloids 211
14 Occurrence of Purine Alkaloids 213
14.1 Introduction 213
14.2 Chemical Structure of Purine Alkaloids 213
14.3 Occurrence of Purine Alkaloids in Plants 215
14.4 Summary 226
References 226
15 Biosynthesis of Purine Alkaloids 231
15.1 Introduction 231
15.2 A Brief History of Caffeine Biosynthesis Research 231
15.3 Caffeine Biosynthesis Pathway 234
15.4 Genes and Proteins of Caffeine Synthase Family 245
15.5 Xanthosine Biosynthesis from Purine Nucleotides 249
15.6 Summary 253
References 253
16 Physiological and Ecological Aspects of Purine Alkaloid Biosynthesis 259
16.1 Introduction 259
16.2 Physiology of Caffeine Biosynthesis 259
16.3 Subcellular Localization of Caffeine Biosynthesis 268
16.4 Regulation of Caffeine Biosynthesis 270
16.5 Ecological Roles of Caffeine 271
16.6 Summary 274
References 275
17 Metabolism of Purine Alkaloids and Biotechnology 281
17.1 Introduction 281
17.2 Metabolism of Purine Alkaloids 281
17.3 Diversity of Purine Alkaloid Metabolism in Plants 285
17.4 Biotechnology of Purine Alkaloids 293
17.5 Caffeine-Producing Transgenic Plants 295
17.6 Summary 298
References 298
Part VI Pyridine Nucleotide Metabolism 301
18 Pyridine (Nicotinamide Adenine) Nucleotide Biosynthesis De Novo 303
18.1 Introduction 303
18.2 Two Distinct Pathways of De Novo Nicotinate Mononucleotide Biosynthesis 303
18.3 The Outline of the De Novo Pathway of NAD Biosynthesis in Plants 304
18.4 Enzymes Involved in De Novo NAD Synthesis in Plants 307
18.5 Summary 310
References 310
19 Pyridine Nucleotide Cycle 315
19.1 Introduction 315
19.2 Pyridine Nucleotide Cycle 315
19.3 Catabolism of NAD 320
19.4 Enzymes Involved in NAD Catabolism 321
19.5 Salvage of Nicotinamide and Nicotinate 323
19.6 Summary 325
References 325
Part VII Pyridine Alkaloids 329
20 Occurrence and Biosynthesis of Pyridine Alkaloids 331
20.1 Introduction 331
20.2 Occurrence of Pyridine Alkaloids 333
20.3 Biosynthesis of Pyridine Alkaloids 335
20.4 Summary 345
References 345
21 Physiological Aspect and Biotechnology of Trigonelline 351
21.1 Introduction 351
21.2 Physiological Aspect of Trigonelline Biosynthesis 351
21.3 Physiological Aspect of Nicotinate N-Glucoside Biosynthesis 356
21.4 The Role of Trigonelline in Plants 356
21.5 Biotechnology of Trigonelline 360
21.6 Summary 362
References 363
Part VIII Other Nucleotide-Related Metabolites 367
22 Sugar Nucleotides 369
22.1 Introduction 369
22.2 The Sugar Nucleotide Moiety 370
22.3 Enzymes of Sugar Nucleotide Biosynthesis 371
22.4 Localization of UDP-Glucose-Producing Enzymes 377
22.5 UDP-Glucose-Interconversion 377
22.6 Other Metabolites 379
22.7 Summary 382
References 382
23 Cytokinins 387
23.1 Introduction 387
23.2 Adenosine Phosphate-Isopentenyl Formation 388
23.3 trans-Zeatin Phosphate Synthesis 389
23.4 Formation of Cytokinin Bases 389
23.5 Effect of Nucleotide Enzymes in Cytokinins 390
23.6 New Purine-Related Plant Growth Regulators 392
23.7 Summary 393
References 394
Part IX Dietary Plant Alkaloids, Their Bioavailability, and Potential Impact on Human Health 397
24 Bioavailability and Potential Impact on Human Health of Caffeine, Theobromine, and Trigonelline 399
24.1 Caffeine 399
24.2 Theobromine 404
24.3 Trigonelline 406
24.4 Summary 409
References 409
Index 415
