Description
Key facts
Detection method:Fluorescent,
Sample types:Urine, Plasma, Cell culture extracts,
Assay type:Quantitative,
Assay time:20m,
Assay Platform:Microplate reader
Product details:
Free Thiol Assay Kit (Fluorometric) (ab112158) provides an ultrasensitive fluorometric assay to quantitate thiol content that exists in small molecules such as free cysteine, glutathione, and cysteine residues.
This product is not suitable for assaying thiols incorporated within proteins. It is designed for thiols in free small molecules like amino acids.
The assay is based on a proprietary non-fluorescent dye tha generates a strongly fluorescent adduct upon reacting with a thiol compound. The signal produced by the adduct can be easily read by a fluorescence microplate reader at Ex/Em = 490/520 nm. In addition, both absorption and emission spectra of the thiol adduct are pH-independent, making the assay highly robust. There are few reagents or assay kits available for quantitating thiol content in biological systems, and the majority of commercial kits either lack sensitivity or have tedious protocols. The assay can detect as little as 1 picomole of cysteine or GSH in a 100 uL assay volume (10 nM).
Please note it is not possible to do a quantification in comparison to the standard.
Free Thiol assay protocol summary:
- add samples and standards to wells
- add reaction mix
- analyze with microplate reader for 10 min to 1 hr
Other Notes
This product was previously called Thiol Quantification Assay Kit (Fluorometric).
This product detects thiol groups on small molecules. If you want to detect thiol groups in proteins, we recommend Total Protein Thiol Quantification Assay Kit (Colorimetric) (ab219272)
Properties and Storage Information:
Shipped at conditions-Blue Ice, Appropriate short-term storage conditions--20°C, Appropriate long-term storage conditions--20°C, Storage information--20°C
Supplementary Information:
This supplementary information is collated from multiple sources and compiled automatically.
Thiol groups often referred to as mercaptans are functional groups consisting of a sulfur atom bonded to a hydrogen atom. They are found in various biological compounds like proteins and peptides. Notably cysteine residues often contain thiol groups contributing to protein thiols and their reactivity. Thiols can form disulfide bonds leading to alterations in protein structure and function. Protein thiols are frequently expressed in various tissues and serve as active sites for many enzymes due to their nucleophilic nature. The molecular mass of a thiol group itself is relatively small around 34.08 Dalton but it plays an essential role in the overall mass and function of larger biomolecules.
Biological function summary
Thiol groups in cysteine residues participate in forming disulfide bridges which are critical for maintaining protein structure and stability. These links can affect the protein's shape and function and they change based on the cellular environment. Some proteins possess dithiol groups due to the presence of multiple thiol pairs making them active in catalytic functions. These proteins may be part of larger complexes like enzymes that catalyze redox reactions influencing processes such as cellular respiration and detoxification pathways.
Pathways
Thiol-containing proteins play significant roles in redox balance and signal transduction. These proteins participate in pathways such as the oxidative stress response and cellular signaling cascades. For example glutathione a tripeptide with a thiol group is critical in the antioxidant pathway protecting cells from oxidative damage with enzymes like glutathione peroxidase. Moreover thiol groups can modulate the function of transcription factors impacting gene expression pathways by altering DNA and protein interactions.
Mutations or alterations in thiol groups can be linked to conditions such as Alzheimer's disease and cystic fibrosis. In Alzheimer's oxidative stress alters protein thiol-disulfide exchanges damaging neuronal proteins. In cystic fibrosis disruptions in thiol-dependent pathways may interfere with protein folding. The protein thiol's interaction with others like amyloid precursor protein (in Alzheimer's) or chloride channels (in cystic fibrosis) highlights its potential role in disease modulation. Understanding thiol dynamics can lead to therapeutic strategies targeting these diseases.
