166734-64-1Relevant articles and documents
Calorimetric Evaluation of Enzyme Kinetic Parameters
Williams, Brent A.,Toone, Eric J.
, p. 3507 - 3510 (1993)
The measurement of kinetic parameters (kcat, Km, Ki) for a wide range of proteolytic enzymes is vital to contemporary bioorganic and medicinal chemistry.Enzyme assays based on changes in optical properties of the system or changes in concentration of an ion detectable electrochemically are not viable for many enzyme-catalyzed reactions, including proteases and peptidases.Hydrolysis of an amide bond produces no change in the optical properties or pH of the reaction solution, and as a result no general direct method for the evaluation of protease kinetics exists using underivatized substrates.We report here a microcalorimetric assay which provides a general and straightforward technique for the measurement of kinetic parameters of hydrolysis of underivatized peptide substrates by proteases.Using this technique, kcat values as high as 105 s-1 can be easily measured.We demonstrate the utility of the technique by measuring the kinetics of hydrolysis of several N-acylamino acids by the synthetically useful enzyme hog kidney acylase and the hydrolysis of tetrapeptide p-nitrophenyl anilides by subtilisin BPN'.Although we have used the technique to monitor amide bond hydrolysis, the methodology is applicable to any system with appropriate kinetic and thermodynamic properties.
Improved synthesis of unnatural amino acids for peptide stapling
Li, Bo,Zhang, Jie,Xu, Yongjuan,Yang, Xiaoxiao,Li, Li
, p. 2374 - 2377 (2017/05/29)
The procedures for the synthesis of various α-alkenyl and alkyne amino acids were systematically optimized in light of enhancing atom economy, reducing hazardous reagent usage, and simplifying workup. By starting with Boc-Pro-OH and coupling with EDCI/DMAP followed by alkylation, chiral auxiliary was synthesized with high yield and enantioselectivity. For alkylation of the chiral complex, tBuONa was found and proved by quantitative calculation to be superior to tBuOK in generating more nucleophilic enolate salt, thereby can significantly enhance yield under room temperature. Final Fmoc protection was also dramatically facilitated in one-pot sequential manner by adding EDTA-2Na as the nickel chelator. Synthesis of α-bisalkenyl amino acid was also accomplished by achiral complex approach with high yield and efficacy. Accordingly, five most commonly used N-Fmoc protected α-alkenyl and alkynyl amino acids were synthesized and characterized.
Influence of α-methylation in constructing stapled peptides with olefin metathesis
Zhang, Qingzhou,Shi, Xiaodong,Jiang, Yanhong,Li, Zigang
, p. 7621 - 7626 (2014/12/11)
Ring-closing metathesis is commonly utilized in peptide macro-cyclization. The influence of α-methylation of the amino acids bearing the olefin moieties has never been systematically studied. In this report, controlled reactions unambiguously indicate that α-methylation at the N-terminus of the metathesis sites is crucial for this reaction to occur. Also, we first elucidated that the E-isomers of stapled peptides are significantly more helical than the Z-isomers.
