definition
Nucleotides are chemical compounds that consist of purine or pyrimidine bases, ribose or deoxyribose molecules, and phosphoric acid. These units are also referred to as nucleosides. Nucleotides are synthesized by combining organic bases and five-carbon sugars. When nucleosides combine with phosphoric acid, nucleotides are formed. Nucleic acids, which are made up of four kinds of nucleotides, are involved in complex biological functions.
Nucleotides play a critical role in the formation of nucleic acids, but individual nucleotides also have vital biological functions. For instance, adenosine triphosphate (ATP) and dehydrogenation coenzymes, which help generate energy in biochemical reactions, are composed of nucleotides. Certain nucleotide analogs can interfere with the metabolism of nucleotides. As a result, these analogs are used as anticancer drugs.
Ribonucleotides and deoxynucleotides are two types of nucleotides, which differ based on the type of sugar. Meanwhile, nucleotides containing adenine (adenylic acid, AMP), guanine (guanylic acid, GMP), cytosine (cytidine acid, CMP), uracil (uridine acid, UMP), thymine (thymidylic acid, TMP), and hypoxanthine (inosinic acid, IMP) are distinguished based on the type of base present.
Nucleotides containing phosphoric acid can form one, two, or three molecules of this compound. Additionally, nucleotide molecules can undergo dehydration and condensation to form cyclic nucleotides. Overall, nucleotides are essential building blocks in biochemistry and have a wide range of functions within the human body.
synthesis
The basic building block for synthesizing ribonucleic acid and deoxyribonucleic acid is the nucleotide. These are found in the nucleus and cytoplasm of cells and are used to participate in various life activities, such as genetics, development, and growth of organisms. Nucleotides can exist in a free form within the body, and adenosine triphosphate is especially important in cell energy metabolism. This molecule's production and consumption reflect the energy release and absorption ability of the body. Other nucleotides such as uridine triphosphate, cytidine triphosphate, and guanosine triphosphate also serve as energy sources during the synthesis and metabolism of some substances. Additionally, adenylate is an essential component of some coenzymes, including coenzyme I, II, and coenzyme A.
Simple compounds like glycine, aspartic acid, glutamine, one-carbon unit, and CO2 can be utilized by organisms to synthesize nucleotides. Purine nucleotides can be broken down to generate uric acid while pyrimidine nucleotides can be metabolized to create CO2, β-alanine and β-aminoisobutyric acid. In the body, disorders that affect the metabolism of purine and pyrimidine nucleotides can lead to clinical symptoms. Refer to Pyrimidine Metabolism Disorders and Purine Metabolism Disorders for more information.
Drugs used for clinical treatment often contain nucleotide compounds like 5-fluorouracil and 6-mercaptopurine. These compounds are particularly effective in tumor chemotherapy, helping to combat cancerous cells in affected patients.
Nucleotides come in various forms, such as nucleoside monophosphate (NMP), which contains only a single phosphate group. Additional phosphorylation of the 5'-nucleotide can give rise to nucleoside diphosphate (NDP) and nucleoside triphosphate (NTP), which possess high-energy bonds in their phosphate group linkages. This process also applies to deoxynucleotides, which can undergo phosphorylation to yield NDP and NTP forms with increased energy in their phosphate linkages. Overall, nucleotide molecules display a range of structures that allow for diverse biochemical actions within cells.
Another type of cyclic nucleotide found in the body is formed by the dehydration and condensation of the phosphoric acid part of a single nucleotide and the third and fifth carbon atoms in ribose. This results in the formation of a cyclic diester, known as 3',5'-cyclic nucleotide. The two most notable cyclic nucleotides are 3',5'-cyclic adenosine acid (cAMP) and 3',5'-cyclic guanosine acid (cGMP).
