Description

[3-(Trimethylammonium)Propyl] Methanethiosulfonate Bromide is a high-purity, reactive organosulfur compound widely used as a key reagent for site-directed spin labeling and protein modification. Its primary value lies in its ability to selectively introduce a stable, paramagnetic nitroxide spin label onto cysteine residues, enabling advanced structural and dynamic studies of biomolecules via Electron Paramagnetic Resonance (EPR) spectroscopy. This product is essential for researchers and manufacturers in the fields of structural biology, biophysics, and pharmaceutical development who require precise tools for probing protein structure, function, and conformational changes.

Application

• Site-Directed Spin Labeling (SDSL): Primary reagent for covalently attaching methanethiosulfonate (MTSL) spin labels to engineered cysteine residues in proteins for EPR studies.
• Protein Structure & Dynamics Analysis: Enables the investigation of protein folding, conformational changes, oligomerization, and interactions through distance measurements via pulsed EPR techniques like DEER/PELDOR.
• Membrane Protein Research: Critical tool for labeling and studying the structure and dynamics of challenging membrane-embedded proteins.
• Biophysical Probe Development: Used to create spin-labeled nucleotides, lipids, or other biomolecules to study complex biological assemblies and enzymatic mechanisms.
• Pharmaceutical R&D: Aids in drug discovery by mapping ligand-binding sites and characterizing allosteric mechanisms within target proteins.
• Quality Control Reference Standard: Serves as a high-purity analytical standard for method development and validation in laboratories specializing in spin-labeling chemistry.

Basic Information

Product Name	[3-(Trimethylammonium)Propyl] Methanethiosulfonate Bromide
CAS No.	220560-60-1
Molecular Formula	C7H16BrNO2S2
Molecular Weight	282.24 g/mol
Synonyms	(1-Oxy-2,2,5,5-tetramethyl-δ3-pyrroline-3-methyl) Methanethiosulfonate; MTSL; (2,2,5,5-Tetramethyl-1-oxyl-3-pyrrolidinyl)methyl Methanethiosulfonate; 3-Maleimido-PROXYL Methanethiosulfonate (common misnomer); S-(1-Oxy-2,2,5,5-tetramethylpyrrolidin-3-ylmethyl) Methanethiosulfonate; 3-Maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxy Methanethiosulfonate; MTSSL; Nitroxide Spin Label Reagent
EINECS	Contact for details

Quality Control

Our [3-(Trimethylammonium)Propyl] Methanethiosulfonate Bromide is manufactured under strict quality control protocols to ensure the high purity and consistency required for sensitive biophysical research. Each batch is fully characterized and tested to meet exacting specifications. A comprehensive Certificate of Analysis (COA) detailing purity, identity, and impurity profiles is provided with every shipment to support your research and regulatory documentation needs.

Storage

Preserve in a tightly closed container, protected from light. Store at 2-8°C in a dry, cool place. This product is hygroscopic (moisture-sensitive) and light-sensitive; prolonged exposure to ambient conditions, moisture, or light may lead to decomposition. For long-term stability, consider storage under an inert atmosphere such as argon or nitrogen.

Specification

Item	Specification
Appearance	White to off-white crystalline solid
Identification (IR)	Conforms to structure
Identification (HPLC)	Retention time matches reference standard
Purity (HPLC)	≥ 98.0%
Water Content (KF)	≤ 0.5%
Residue on Ignition	≤ 0.1%

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