D-Isoleucine is the D-stereoisomer of the proteinogenic amino acid isoleucine, featuring a branched aliphatic side chain that contains a secondary carbon and a terminal methyl group. The molecule bears a free α-amino group and a free α-carboxyl group, with stereochemistry at the α-carbon corresponding to the D configuration implied by the product name. As a free amino acid, D-Isoleucine is used in peptide chemistry for preparing dipeptides or incorporating the D-amino acid into synthetic peptides, and it also serves as a defined substrate or reference material in analytical method development and stereochemical studies.
D-Isoleucine is a chiral branched-chain amino acid with the (2S,3R)-configured side chain typical of D-amino acid stereochemistry, featuring a primary amino group and a carboxylic acid functional group on the α-carbon framework. The isoleucine side chain contains a secondary carbon and an isopropyl-like motif that imparts hydrophobic character and conformational bias, which can influence peptide backbone preferences and side-chain packing in biomolecular contexts. As the free amino acid, D-Isoleucine participates in standard amino acid coupling chemistry through its carboxylate and can be converted into protected amino acid derivatives or esters for controlled reactivity. The stereochemical definition makes D-Isoleucine suitable for chiral building block design, racemate resolution workflows, and downstream formation of D-configured peptide segments and synthetic intermediates.
1. Peptide Synthesis
D-Isoleucine is applied in peptide synthesis and peptidomimetic construction where D-amino acid incorporation is used to control proteolytic stability and stereochemical presentation along the peptide backbone. The amino and carboxyl groups enable conversion into N-protected, C-activated building blocks compatible with amide bond formation, while the branched hydrophobic side chain supports formation of well-defined internal hydrophobic contacts in peptide analogs. D-Isoleucine-derived residues can be introduced at specific positions to tune conformational behavior and to generate D-configured peptide libraries for screening and SAR studies. The resulting D-isoleucine-containing peptides and analogs serve as research-grade scaffolds for studying sequence-dependent structure and synthetic methodology.
2. Unnatural Amino Acid Incorporation
D-Isoleucine is used as a chiral amino acid intermediate for unnatural amino acid incorporation into peptides and engineered biomolecules, leveraging its defined D-configuration at the α-stereocenter. The side-chain branching provides a distinct steric and hydrophobic profile relative to L-isoleucine, enabling stereochemically controlled modulation of local backbone geometry and side-chain orientation. Protected amino acid derivatives derived from D-Isoleucine can be assembled into longer sequences using standard peptide coupling strategies, with protecting-group selection supporting orthogonal deprotection for iterative chain extension. Downstream, D-Isoleucine-containing constructs can be used to generate stereochemically defined analogs for chemical biology research and structure-activity relationship studies.
3. Chiral Derivatization Chemistry
D-Isoleucine is suitable for chiral synthesis workflows and analytical derivatization chemistry where amino acid stereocenters act as reliable chiral handles. The primary amine and carboxylic acid can be transformed into N-acyl derivatives, esterified forms, or activated intermediates that participate in forming diastereomeric products with chiral reagents or substrates. D-Isoleucine-based derivatives can support development of chiral standards and intermediate building blocks for stereochemical assignment, enantiomeric enrichment, and method development in synthetic organic chemistry. The defined D-configuration helps maintain stereochemical traceability through downstream transformations and product characterization.
4. Pharmaceutical Intermediate Preparation
D-Isoleucine is employed in pharmaceutical intermediate preparation and process chemistry as a stereochemically defined amino acid feedstock for generating D-configured fragments used in medicinal chemistry and peptide-based ingredient development. The ability to convert the free amino acid into N-protected amino acid derivatives, activated esters, or coupling-ready intermediates supports manufacturing-oriented route design where controlled reactivity and predictable deprotection behavior are required. The branched hydrophobic side chain can be carried through as a stable motif in peptidomimetic and amino acid-derived scaffolds that undergo further functional group transformations. D-Isoleucine-derived intermediates can therefore serve as inputs for fine chemical synthesis and downstream elaboration into D-amino acid containing structures used in applied R&D programs.
5. Bioconjugation And Biomolecule Modification
D-Isoleucine is applicable to bioconjugation and biomolecule modification strategies where D-amino acid segments are used to modulate stability and reduce susceptibility to proteolysis during conjugate handling. The functional groups enable preparation of protected derivatives that can later be deprotected to reveal reactive amines or carboxylates for coupling to activated linkers, surfaces, or carrier proteins. The hydrophobic branched side chain can influence local conjugate microenvironment and can be incorporated into linker regions to affect solubility and steric accessibility. D-Isoleucine-containing conjugates and linkers can be used in chemical biology research to create stereochemically defined biomolecule constructs and to support analytical characterization of conjugation outcomes.
2. Autoinhibition and phosphorylation-induced activation of phospholipase C-γ isozymes
3. Adipose tissue is a key organ for the beneficial effects of GLP-2 metabolic function
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