11: Nucleotide and nucleic acid structure and metabolism
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- 11.1: Structure and Function - Nucleic Acids
- The nucleic acids, DNA and RNA, may be thought of as the information molecules of the cell. In this section, we will examine the structures of DNA and RNA, and how these structures are related to the functions these molecules perform.
- 11.2: Pyrimidine de novo Biosynthesis
- Starting materials for pyrimidine biosynthesis include bicarbonate, amine from glutamine, and phosphate from ATP to make carbamoyl-phosphate (similar to the reaction of the urea cycle). Joining of carbamoyl phosphate to aspartic acid (forming carbamoyl aspartate) is catalyzed by the most important regulatory enzyme of the cycle, aspartate transcarbamoylase (also called aspartate carbamoyltransferase or ATCase).
- 11.3: Deoxyribonucleotide de novo Biosynthesis
- Synthesis of deoxyribonucleotides de novo requires an interesting enzyme called ribonucleotide reductase (RNR). RNR catalyzes the formation of deoxyribonucleotides from ribonucleotides. The most common form of RNR is the Type I enzyme, whose substrates are ribonucleoside diphosphates (ADP, GDP, CDP, or UDP) and the products are deoxyribonucleoside diphosphates (dADP, dGDP, dCDP, or dUDP). Thymidine nucleotides are synthesized from dUDP.
