Description

Sulforhodamine Methanethiosulfonate is a high-purity, bifunctional labeling reagent designed for the site-specific modification of cysteine residues in proteins and peptides. This compound is critical for researchers and manufacturers requiring precise, stable fluorescent tagging for advanced analytical and diagnostic applications. It is primarily utilized in the life sciences sector for applications in bioconjugation, fluorescence microscopy, and the development of bioassays and biosensors.

Application

• Bioconjugation & Protein Labeling: Site-specific covalent attachment of a fluorescent sulforhodamine dye to thiol groups (-SH) on cysteine residues for creating labeled proteins.
• Fluorescence Microscopy & Imaging: Preparation of brightly fluorescent probes for cellular and subcellular imaging studies due to its high quantum yield and photostability.
• Biomolecular Assay Development: Key reagent in the synthesis of fluorescent tracers and detection molecules for ELISA, fluorescence polarization (FP), and other high-throughput screening (HTS) assays.
• Biosensor Fabrication: Used to functionalize surfaces or nanoparticles with fluorescent tags for the development of optical biosensors.
• Structural Biology Studies: Fluorescent labeling of proteins for Förster Resonance Energy Transfer (FRET) experiments to study protein-protein interactions and conformational changes.
• Diagnostic Reagent Synthesis: Intermediate in the production of fluorescent antibodies and other diagnostic conjugates.

Basic Information

Product Name	Sulforhodamine Methanethiosulfonate
CAS No.	386229-71-6
Molecular Formula	C27H21N2O7S3+ • X-
Molecular Weight	Approx. 581.66 g/mol (for cation)
Synonyms	Texas Red® Maleimide Alternative; Texas Red® Methanethiosulfonate; Sulforhodamine 101 Methanethiosulfonate; MTS-Sulforhodamine 101; SR101-MTS; Alexa Fluor® 594 MTS Analog; Thiol-Reactive Sulforhodamine Dye; 6-((2-((2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)methoxy)ethyl)thio)-3H-xanthen-3-ylidene)-N-ethyl-1,3-benzothiazol-3-ium-6-amine
EINECS	Contact for details

Quality Control

Our Sulforhodamine Methanethiosulfonate is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing, including HPLC for purity, NMR and MS for structural confirmation, and functional testing for labeling efficiency. A comprehensive Certificate of Analysis (COA) detailing identity, purity, and performance specifications is provided with every shipment to ensure traceability and compliance with research-grade standards.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C or below under desiccant. This material is hygroscopic (moisture-sensitive) and light-sensitive. Allow the vial to equilibrate to room temperature in a desiccator before opening to minimize moisture uptake.

Specification

Item	Specification
Appearance	Dark red to purple solid
Identification (HPLC)	Retention time corresponds to reference standard
Identification (MS)	Consistent with molecular structure
Purity (HPLC)	≥ 95% (Area %)
Water Content (KF)	≤ 2.0 %
Functional Activity (Labeling)	≥ 90% coupling efficiency with standard thiol

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.