Detection of L-Proline-Catalyzed Michael Addition Reaction in Model Biomembrane

Abstract

A method to detect the L-proline- (L-Pro-) catalyzed Michael addition reaction in model biomembranes has been established, using N-[p(2-benzimidazolyl)phenyl]maleimide and acetone as reactants. The effect of liposome membranes on this reaction was kinetically analyzed using fluorescence spectroscopy. The kinetics of the reaction were different from those of the constituent lipids of the liposomes. Zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposome, which is in the solid-ordered phase, had a better value of reaction rate, suggesting that the reaction rate constants of this reaction in liposome membrane systems could be regulated by the characteristics of the liposome membrane (i.e., the phase state and surface charge). Based on the results obtained, a plausible model of the L-Pro-catalyzed Michael addition reaction was discussed. The obtained results provide us with an easily detectable method to assess the reactivity of L-Pro in biological systems.

A bifunctional molecular catalyst built up of l-proline grafted polyoxometalate for one-pot three-component green synthesis of heterocycles

“…Particularly, l -proline ( l -pro) is widely used as a natural organocatalyst with the advantages of a simple structure, abundant natural reserves and low price, which can catalyze a variety of organic synthesis reactions such as Mannich, 16 Aldol, 17 and Michael. 18 In recent years, numerous studies have been conducted on the synthesis of heterocyclic compounds using l -proline as a green catalyst, among which pharmacological activities are found in some heterocyclic compounds. 19 For example, 5-aryl-pyrimido[4,5- b ]quinoline-dione derivatives 20 (Fig.…”

Formal [4 + 2] Cycloadditions of Maleimides on Duplex DNA

“…In contrast, higher reaction rate constants ( k ) were observed for VdU as compared to BDdU according to both fluorescence and NMR-based assays. Using pseudo-first-order approximations with the nucleosides in vast excess as compared to the fluorogenic maleimide N -( p -(2-benzimidazolyl)­phenyl)­maleimide (BIPM), second-order rate constants of 4.9 × 10 –2 s –1 M –1 for VdU ( 1 ) and 1.8 × 10 –2 s –1 M –1 for BDdU ( 2 ) were observed in a 1:1 mixture of H 2 O/DMSO (Figure S2, Supporting Information). However, slow hydrolysis of maleimide was also observed under these conditions, giving baseline changes in fluorescence.…”