I. Chemical Structure and Protecting Group Advantages
As an amino-protected derivative of L-lysine, its N6-amino group is modified by a benzyloxycarbonyl (Cbz) group, endowing unique stability:
Acid-base Tolerance: Stable in neutral to weak alkaline environments (pH 6–9), resisting spontaneous deprotection to avoid premature amino group reactions in peptide synthesis.
Antioxidant and Anti-condensation Capability: The benzene ring of Cbz defends against oxidative damage and prevents amino group condensation with aldehydes/ketones, ensuring structural integrity during storage and reactions.
Selective Deprotection Advantage: The protecting group can be specifically removed via catalytic hydrogenation (H₂/Pd-C) or acidolysis (e.g., trifluoroacetic acid) without affecting other functional groups, meeting orthogonal protection needs in peptide synthesis.
II. High-efficiency Reactivity in Peptide Synthesis
As a key intermediate, its reactivity is reflected in:
High Coupling Efficiency: Cbz-protected amino groups show >95% coupling efficiency with carboxyl groups under condensing agents (e.g., DCC, HATU), yielding products with low by-products and HPLC purity ≥98%.
Bifunctional Modifiability: The α-carboxyl and N2-amino groups participate in peptide bond formation, while the Cbz-protected N6-amino group can be selectively activated for functional modifications (e.g., introducing PEG chains, fluorescent groups).
Chiral Configuration Stability: The L-configuration chiral center resists racemization under conventional conditions, ensuring optical purity for synthesizing bioactive chiral molecules.
III. Biocompatibility and Metabolic Characteristics
Low Cytotoxicity: In vitro experiments (concentration ≤1 mM) show <5% proliferation inhibition rate on mammalian cells (e.g., HEK293), suitable for peptide drug and biological probe preparation.
In vivo Metabolic Stability: Compared with protecting groups like Fmoc/Boc, Cbz degrades more slowly in enzymatic environments, serving as a protective structure for long-acting peptide precursors to extend drug half-life.
Solubility and Crystallization Advantages: Moderate solubility in DMF, DMSO, and water, with a regular crystal structure (melting point 150–155℃) for easy recrystallization purification.
IV. Storage and Handling Convenience
Room-temperature Stability: Shelf life ≥2 years under dark storage at room temperature, eliminating the need for low-temperature freezing and reducing storage costs.
Safe and Easy Handling: Non-flammable, odorless, and operable with routine laboratory protection—easier to process than protectants with high-risk groups.
V. Potential for Multifunctional Derivative Applications
Beyond peptide synthesis, its Cbz-protected amino group can participate in polymerization to prepare functional polymers, or be further functionalized via benzyl oxidation/halogenation, providing a structural basis for synthesizing fine chemicals like chiral ligands and amino acid-based surfactants, expanding into materials science and chemical engineering.
