3-(Cyclohexylamino)-2-hydroxy-1-propanesulfonic acid
[CAS# 73463-39-5]

Identification

• Classification: Chemical reagent >> Organic reagent >> Sulfonic acid / sulfinic acid
• Name: 3-(Cyclohexylamino)-2-hydroxy-1-propanesulfonic acid
• Synonyms: CAPSO
• Molecular Formula: C₉H₁₉NO₄S
• Molecular Weight: 237.31
• CAS Registry Number: 73463-39-5
• EC Number: 615-979-5
• SMILES: C1CCC(CC1)NCC(CS(=O)(=O)O)O

Properties

• Solubility: 0.1 g/mL (water)
• Melting point: 270-274 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P233-P260-P261-P264-P271-P280-P302+P352-P304-P304+P340-P305+P351+P338-P312-P321-P332+P313-P337+P313-P340-P362-P403-P403+P233-P405-P501

Discovery and Applications

3-(Cyclohexylamino)-2-hydroxy-1-propanesulfonic acid, commonly known as CAPS, was developed in the 1960s as part of an effort to create Good's buffers. These buffers were designed by Norman Good and his colleagues to meet specific needs in biological and biochemical research. CAPS belongs to the family of zwitterionic buffers, which are able to maintain stable pH levels without interfering with biological processes.

CAPS is a zwitterionic buffer with the molecular formula C9H19NO4S. It has a high buffering capacity over the pH range of 9.7 to 11.1 and a pKa of 10.4 at 25°C. This makes it particularly useful for applications that require an alkaline pH. CAPS is highly soluble in water, enhancing its usefulness in a variety of experimental conditions.

CAPS is widely used in protein and nucleic acid electrophoresis. Its ability to maintain a stable alkaline pH ensures that proteins and nucleic acids migrate correctly during electrophoresis, resulting in accurate and reproducible results.

CAPS is used in a variety of biological experiments, especially those involving enzymatic reactions that require an alkaline environment. It is ideal for maintaining the desired pH without introducing contaminants that could interfere with reactions.

In protein purification protocols, CAPS provides a stable pH environment that is critical for binding and elution processes in ion exchange chromatography. This stability ensures that the protein maintains its function and structure throughout the purification process.

CAPS is used in biochemical assays where maintaining an alkaline pH is critical. It helps stabilize pH for consistent and reliable results in enzyme assays and other biochemical reactions.

CAPS offers several advantages, including high solubility in water and minimal absorbance in UV and visible light, which reduces interference with spectrophotometric measurements. Its chemical stability and resistance to enzymatic degradation ensure that it remains effective over extended periods of time and under a variety of experimental conditions.

References

1990. Application of a new pH-sensitive fluoroprobe (carboxy-SNARF-1) for intracellular pH measurement in small, isolated cells. Pflügers Archiv - European Journal of Physiology.
DOI: 10.1007/bf00370705

1986. Multiple activation currents can be evoked in Xenopus laevis eggs when cortical granule exocytosis is inhibited by weak bases. Pflügers Archiv - European Journal of Physiology.
DOI: 10.1007/bf00652620