H-D-beta-HPro-OH*HCl

H-D-beta-HPro-OH*HCl is a hydrochloride salt form of a protected, stereochemically defined proline-derived amino acid building block featuring a cyclic pyrrolidine side chain (proline backbone) and a free carboxylic acid functionality paired with an N-substituted deuterated motif (H-D at the β-position). The presence of the HCl salt indicates protonation of the basic nitrogen, improving handling and enabling consistent coupling behavior under peptide synthesis conditions. The deuterium incorporation at a defined position supports kinetic isotope effect studies, NMR/IR isotopologue tracking, and mass-spectrometric discrimination in biochemical and analytical workflows. The combination of a chiral proline framework with a reactive carboxylic acid and a protected/controlled nitrogen environment makes the compound suitable for peptide building block preparation and downstream synthetic transformations into labeled peptide analogs.

1. Peptide Synthesis

H-D-beta-HPro-OH*HCl is applied in peptide synthesis workflows where proline-containing sequences require stereochemically controlled amino acid incorporation. The cyclic proline side chain and the carboxylic acid enable standard peptide coupling chemistry, while the N-state associated with the deuterated β-substitution supports incorporation of an isotopically defined residue without scrambling at the stereocenter. Hydrochloride salt formation can facilitate reproducible solvation and consistent reactivity during protected amino acid handling and coupling steps. Labeled proline residues derived from this compound can be used to construct deuterated peptides for mechanistic studies of amide bond formation, conformational effects of proline, and peptide stability assessments.

2. Isotope-Labeled Biochemistry

H-D-beta-HPro-OH*HCl supports chemical biology and biochemical research requiring position-specific deuterium labeling of proline residues. The deuterium at the β-related position provides a measurable isotopic signature for LC-MS/MS, NMR, and IR isotopologue analysis, enabling tracking of incorporation and monitoring of residue-specific transformations in peptide and protein contexts. The proline ring can participate in conformational constraints within labeled peptides, supporting interpretation of structure-function relationships when isotope effects influence backbone dynamics. Downstream labeled peptide or peptidomimetic products prepared from this amino acid can serve as research intermediates for mechanistic enzyme studies, pathway mapping, and quantitative analytical method development.

3. Protein Engineering

H-D-beta-HPro-OH*HCl can be used for protein engineering programs that require incorporation of deuterium-labeled proline analogs into peptide scaffolds and recombinant protein constructs. The amino acid backbone features a proline-compatible geometry that can be translated into peptide segments used for binding studies, folding investigations, or conformational mapping via isotope-sensitive readouts. The hydrochloride salt form supports handling as a chiral amino acid intermediate during synthesis of labeled domains, while the controlled N/C functional group set enables sequential assembly into longer constructs. Labeled proline-containing fragments derived from this compound can then be employed to interrogate local structural effects, protease recognition patterns, or backbone dynamics in engineered protein systems.

4. Analytical Research Standards

H-D-beta-HPro-OH*HCl is suitable for analytical research applications where isotopically defined amino acid and peptide standards are needed for method validation and metabolite identification. The deuterated proline framework provides a distinct mass shift and spectroscopic signature, supporting discrimination from unlabeled proline-containing species in LC-MS workflows and isotope-resolved NMR experiments. The free carboxylic acid and proline ring allow conversion into peptide standards or derivatized intermediates that reflect realistic sample matrices. Use of this compound in standard preparation can improve confidence in quantitation of proline-containing analytes, isotopic incorporation verification, and interpretation of isotope effects in biochemical assays.

5. Process Chemistry Intermediate

H-D-beta-HPro-OH*HCl serves as a chiral amino acid intermediate for process chemistry and fine chemical synthesis routes targeting deuterated peptide building blocks. The hydrochloride salt form can be leveraged to manage basicity and improve reproducible handling during scale-up of protected amino acid transformations and coupling-ready intermediate preparation. The proline scaffold provides a robust, conformationally constrained substrate for downstream derivatization into labeled protected amino acids or activated derivatives used in peptide manufacturing workflows. Deuterium placement at a defined β-related position supports downstream quality control by enabling isotopic identity checks, supporting consistent production of labeled intermediates for research-grade peptide and peptidomimetic synthesis.

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