Cytosine[2]

Updated: 2026-09-15

Overview

Cytosine is a fundamental nucleobase found in DNA and RNA, where it pairs with guanine via hydrogen bonds to form the genetic code. It was first isolated in 1894 and is classified as a pyrimidine derivative. As one of the four primary bases in nucleic acids, cytosine is vital for cellular replication and protein synthesis. In addition to its biological role, cytosine is used in synthetic biology and drug development. Its derivatives, such as cytarabine, are utilized in chemotherapy. The compound is commercially available in high-purity forms for research and industrial applications.

Physical and Chemical Properties

Cytosine appears as a white crystalline powder with a molecular weight of 111.10 g/mol. It decomposes at 320-325°C and is soluble in water, making it suitable for aqueous biochemical applications. The compound's planar structure facilitates its role in base pairing within DNA helices. Key chemical properties include its weak basicity (pKa ~4.5) and ability to undergo tautomerization, which can lead to rare mutations if mismatched during replication. Stability under standard storage conditions (room temperature, dry environment) ensures long shelf life for laboratory use.

Main Applications

In biotechnology, cytosine is critical for PCR amplification, DNA sequencing, and gene editing technologies like CRISPR. Pharmaceutical companies employ it in antiviral and anticancer drugs, particularly as a component of nucleoside analogs. Industrial applications include its use as a precursor for synthesizing modified nucleobases in agrochemicals and diagnostics. Research-grade cytosine is often packaged with stabilizing buffers for molecular biology workflows.

Safety and Storage

While cytosine itself is not highly toxic, laboratory handling should follow standard biosafety protocols to prevent contamination. Use PPE (gloves, goggles) when weighing powders, and avoid inhalation of dust. For long-term storage, keep containers sealed with desiccants at 2-8°C. Degradation products from moisture exposure may affect experimental results. Dispose of waste according to local regulations for organic compounds.

B2B Procurement Guide

When sourcing cytosine, prioritize suppliers with ISO 9001 certification and batch-specific COAs (Certificates of Analysis). Research-grade material typically requires ≥98% purity verified by HPLC, while industrial grades may tolerate lower purity (95%). Bulk purchases (1kg+) often reduce costs by 20-30%. Consider lead times (2-6 weeks) for custom modifications like isotopic labeling (e.g., 13C/15N for NMR studies). Evaluate shipping options for temperature-sensitive shipments to tropical climates.