Cytidine
[CAS# 65-46-3]

Identification

• Classification: Biochemical >> Nucleoside drugs >> Nucleotides and their analogues
• Name: Cytidine
• Synonyms: 4-Amino-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone; 1-beta-Ribofuranosylosine
• Molecular Formula: C₉H₁₃N₃O₅
• Molecular Weight: 243.22
• Protein Sequence: N
• CAS Registry Number: 65-46-3
• EC Number: 200-610-9
• SMILES: C1=CN(C(=O)N=C1N)[C@H]2[C@@H]([C@@H]([C@H](O2)CO)O)O

Properties

• Solubility: 49 mg/mL (water), 49 mg/mL (DMSO)
• Melting point: 210-217 °C
• alpha: 31.5 ° (c=0.6, H2O 25 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

Cytidine is a nucleoside molecule that is essential to many biological processes. Composed of the nucleobase cytosine linked to a ribose sugar, cytidine plays a central role in nucleic acid synthesis and cellular metabolism. Its discovery and subsequent applications have greatly advanced our understanding of genetics and biochemistry.

Cytidine was first discovered in the early 20th century during studies of the composition of nucleic acids. Scientists discovered that nucleic acids, which make up DNA and RNA, are composed of repeating units called nucleotides. Each nucleotide consists of a nucleoside (a nitrogenous base linked to a sugar) and a phosphate group. Cytidine was found to be one of the four major nucleosides in RNA, alongside adenosine, guanosine, and uridine. This discovery was crucial in elucidating the structure and function of RNA.

Cytidine is essential in RNA synthesis. During transcription, cytidine triphosphate (CTP) pairs with guanine and is incorporated into the RNA chain. This process is essential for translating genetic information from DNA into proteins, which are necessary for cellular structure and function. Without cytidine, RNA synthesis and proper functioning would be impossible.

While cytidine is primarily associated with RNA, its deoxyribose form (deoxycytidine) is a building block of DNA. Deoxycytidine is incorporated into DNA during replication and participates in various DNA repair mechanisms. These processes are essential for maintaining the integrity of genetic information and ensuring accurate transfer of genetic material during cell division.

Cytidine and its derivatives have therapeutic applications, particularly in the treatment of neurological disorders. Cytidine-5'-diphosphocholine (CDP-choline) can be used as a supplement to support cognitive function and treat conditions such as stroke and Alzheimer's disease. CDP-choline is thought to enhance brain function by increasing the synthesis of phospholipids in neuronal membranes and promoting the release of neurotransmitters.

Modified forms of cytidine, such as azacytidine and decitabine, are used in antiviral and anticancer therapies. These analogs can be incorporated into viral or cancerous DNA, thereby inhibiting replication and inducing cell death. For example, azacytidine treats myelodysplastic syndrome and certain types of leukemia by interfering with DNA methylation, a process that affects gene expression and cancer progression.

Cytidine is also used in biochemical research to study various cellular processes. Its role in RNA and DNA synthesis makes it a key molecule for studying gene expression, signal transduction, and enzyme function. Researchers use cytidine analogs to explore the mechanisms of nucleic acid interactions and develop new therapeutic strategies.

References

1971. A Simple New Synthesis of Cytidines. Angewandte Chemie International Edition in English, 10(9).
DOI: 10.1002/anie.197106571

1984. Buffer catalysis of amino proton exchange in compounds of adenosine, cytidine and their endocyclic N-methylated derivatives. Biophysical Chemistry, 20(3).
DOI: 10.1016/0301-4622(84)80013-7