Probes for determining the absolute configuration of D/L-cysteine and/or the enantiomeric composition of cysteine in a sample.

OVERVIEW

Georgetown University researchers synthesized small-molecule probes that are stable for hydrolysis and carry a transferable aryl/heteroaryl moiety for substrate-specific optical analysis of cysteine. This analytical chiral optical sensing assay can rapidly and simultaneously determine the absolute configuration, enantiomeric composition, D/L ratio, and total concentration of free-form cysteine in body fluids. The method relies on fast UV and circular dichroism (CD) measurements to provide accurate stereochemical information covering a wide concentration range of samples in an aqueous solution. The probes can be used to evaluate cysteine wherever cysteine plays an important biological function in its free form, such as in instances of a patient having or suspected of having or at risk of having a disorder mediated by free-form cysteine.

BACKGROUND

The total amount and enantiomeric excess or ratio of amino acids in the Central Nervous System (CNS) play an important role in human physiology and pathology, and they have been associated with neurological disorders such as schizophrenia, Parkinson’s, Huntington’s, and Alzheimer’s disease, as well as other neurodegenerative, psychiatric and other diseases. However, selective stereochemical cysteine analysis is particularly complicated because of the common presence of chemically similar biothiols. In addition to other amino acids, homocysteine (Hcy) and glutathione (GSH) typically interfere with molecular recognition processes and further complicate substrate-specific detection and enantioselective quantification. Therefore, quantifying amino acid concentration and enantiomeric ratio is essential for studying and further developing novel therapeutics for diseases and aging.

Benefit

●Overcomes interference from biothiols and other amino acids such as homocysteine (Hcy) and glutathione (GSH), as seen with other substrate-specific detection methods.

●Compatible with low cysteine concentrations e.g., micromolar.

●Allows rapid and simultaneous determination of the absolute configuration, enantiomeric composition and overall concentration of free-form cysteine

●Compatible with aqueous solutions e.g., body fluids.

Market Application

·It can determine the enantiomeric composition of the desired product, thus indicating the reaction's stereoselectivity.

·It can determine the absolute configuration and enantiomeric composition of cysteine in body fluids, leading to the development of assays using body fluids

·It can be used to analyze small samples to determine cysteine concentration at low concentrations.

·It can rapidly determine the free form of cysteine in aqueous solutions in the presence of other amino acids, decreasing steps including purification of the samples.

Publications

Thanzeel FY, Wolf C. Substrate-Specific Amino Acid Sensing Using a Molecular d/ l-Cysteine Probe for Comprehensive Stereochemical Analysis in Aqueous Solution. Angew Chem Int Ed Engl. 2017 Jun 12;56(25):7276-7281. doi: 10.1002/anie.201701188. Epub 2017 May 16. PMID: 28508583.

United States Patent No. 11,852,633