Nucleotides Metabolism PDF

NUCLEOTIDE METABOLISM Nucleotides have variety of roles in cellular metabolism 1. Precursors for DNA and RNA synthesis 2. Essential carriers of chemical energy, especially ATP and also GTP 3. Components of the cofactors NAD+, FAD, and coenzyme A 4. Act as carriers of active intermediates...

NUCLEOTIDE METABOLISM Nucleotides have variety of roles in cellular metabolism 1. Precursors for DNA and RNA synthesis 2. Essential carriers of chemical energy, especially ATP and also GTP 3. Components of the cofactors NAD+, FAD, and coenzyme A 4. Act as carriers of active intermediates such as UDP-glucose and CDP-diacylglycerol. 5. cAMP and cGMP, are also cellular second messengers, links in response of cells to hormones 6. Allosteric regulation of various metabolic pathways. E.g. ATP inhibits PFK-1. PENTOSE IN NUCLEOTIDES NUCLEOTIDE, NUCLEOSIDE PHOSPHATES de novo synthesis of purine nucleotides require… de novo synthesis of pyrimidine nucleotides requires aspartate as a carbon and nitrogen donor, glutamine as a nitrogen donor, and CO 2 as a carbon donor. Genetic disorders of pyrimidine nucleotide metabolism as a result of defects in either the synthetic or degradative pathways that lead to clinical disorders indicate that the substrate or product is critical for normal cellular function. Interestingly, these defects present in a variety of clinical situations, ranging from anaemia to neurological conditions. Purine nucleotide catabolism PNP Allopurinol Hyperuricemia Hyperuricuria  Gout Gout is caused by precipitation of Sodium urate crystals in the joints resulting in inflammation and pain. Treated by Allopurinol. RIBONUCLEOTIDES  DEOXYRIBONUCLEOTIDES Ribonucleotide Reductase Base pairs Both DNA and RNA contain the same purine bases: adenine (A) and guanine (G); Both DNA and RNA contain the pyrimidine cytosine (C); But they differ in their second pyrimidine base: DNA contains thymine (T), whereas RNA contains uracil (U). T and U differ in that only T has a methyl group. NUCLEOTIDE COENZYME SYNTHESIS