DL-Homocystine is a disulfide-linked amino acid dimer composed of two homocysteine units connected through a central disulfide bond, placing it in the class of cystine-type amino acid derivatives. The molecule contains two amino groups and two carboxyl groups overall, with thiol functionality present as a disulfide (rather than free sulfhydryls), and the "DL-" designation indicates a racemic mixture of stereochemical forms at the relevant chiral centers. In biochemical and synthetic workflows, DL-Homocystine is used as a defined, redox-active precursor for preparing cysteine-containing peptide building blocks and for studying disulfide formation or reduction chemistry in analytical method development and chemical biology experiments.
CAT No: CP06401
DL-Homocystine is a disulfide-linked amino acid dimer composed of two homocysteine units, featuring two stereogenic centers at the homocysteine residues alongside a central S-S bond that can undergo controlled thiol/disulfide interconversion. The molecule presents a polar, zwitterionic character when not fully protected, with side-chain thiol functionality masked as a disulfide and an overall symmetry that supports predictable redox behavior in peptide and bioconjugation contexts. The presence of the disulfide bridge makes DL-Homocystine a practical precursor for generating free thiols under reductive conditions, while its chiral centers exist as a racemic mixture (DL), which influences stereochemical outcomes in downstream coupling, cyclization, and recognition studies. The compound's redox-active disulfide core also enables downstream synthetic utility as an intermediate for disulfide-containing peptide building blocks and for constructing sulfur-rich motifs used in chemical biology and industrial fine chemical synthesis.
1. Peptide Disulfide Building Blocks
DL-Homocystine can be applied in peptide synthesis workflows that require disulfide formation or thiol generation for native-like disulfide scaffolds. The disulfide-linked homocysteine structure provides a direct sulfur-containing motif that can participate in thiol/disulfide exchange chemistry, supporting the construction of cystine-like links in peptide coupling chemistry. Racemic stereochemistry (DL) may be relevant when stereochemical uniformity is not the primary constraint, such as in screening libraries or method development for disulfide installation and exchange. Downstream use can include preparation of disulfide-containing peptide analogs, disulfide-bridged linkers, and sulfur-rich intermediates that integrate into standard peptide coupling and post-coupling oxidation strategies.
2. Chemical Biology Redox Probes
DL-Homocystine serves in chemical biology research where redox-active disulfide chemistry is used to probe thiol-dependent processes and molecular recognition events. The central S-S bond can be converted to reactive thiol species, enabling controlled formation of mixed disulfides or thiol-reactive conjugates that track disulfide exchange pathways. The homocysteine side-chain architecture supports conjugation to electrophilic handles used in biomolecule labeling, while the racemic mixture can be acceptable for mechanistic studies focused on reactivity rather than stereospecific binding. Resulting derivatives can function as disulfide-linked probes, redox-responsive linkers, or intermediate standards for studying sulfur oxidation states in biochemical assays.
3. Bioconjugation Linker Synthesis
DL-Homocystine is suitable for manufacturing and research-oriented preparation of disulfide-based bioconjugation reagents that rely on thiol availability and reversible linkage chemistry. The disulfide core provides a handle for generating thiol-reactive intermediates that can be coupled to maleimide-, haloacetamide-, or other electrophilic functional groups used in biomolecule derivatization. The amino acid backbone contributes polarity and aqueous compatibility, which can support solubility during conjugation steps and downstream purification of conjugate products. Downstream utility includes preparation of disulfide-containing linkers for antibody conjugation studies, enzyme labeling reagents, and intermediate materials for constructing modular conjugates used in applied biochemical research and specialty chemical production.
4. Process Chemistry Intermediate
DL-Homocystine can be employed as a sulfur-rich amino acid intermediate in process chemistry routes that target disulfide-containing fine chemicals and peptide-related building blocks. The molecule's redox-active disulfide and amino acid functionality enable conversion into thiol derivatives, protected thiol intermediates, or disulfide-linked structures that can be carried through multi-step manufacturing sequences. Racemic stereochemistry can simplify procurement and handling when stereochemical purity is not required for the next transformation, while the disulfide motif supports scalable chemistry for sulfur incorporation. Resulting downstream products may include disulfide-containing linkers, sulfur-functionalized intermediates for pharmaceutical intermediate preparation, and process-ready building blocks for industrial synthesis of peptide-like materials.
5. Analytical Standards And Derivatization
DL-Homocystine can be used to develop analytical methods and reference materials for monitoring disulfide species, thiol/disulfide exchange, and sulfur-containing amino acid profiles. The disulfide structure enables derivatization strategies that distinguish oxidized and reduced forms, supporting LC-MS or chromatographic workflows that track redox transformations of homocysteine-related analytes. The presence of two homocysteine residues provides characteristic sulfur content that can improve detectability when coupled with appropriate derivatization reagents. Downstream relevance includes use as a calibration or qualification standard for disulfide-containing intermediates, quality control of amino acid derivative streams, and method development for analytical research in biochemical and industrial settings.
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