Modelling haemoproteins: porphyrins and cyclodextrins as sources of inspiration

Abstract

Associations of hydrophobic cavities with porphyrin derivatives used to mimic haemoprotein structures are featured in this article and may inspire innovative research in the field of cucurbiturils.

Strategies for increasing solubility of porphyrins in aqueous media

“…Fluorescence stability and lifetime experiments confirm that cyclodextrin increases the water solubility of porphyrins [74] . TPPFy-CD(Figure 8e) The presence of positively charged cations and hydrophilic cyclodextrins enhances water solubility [75] . The outer edge of the cyclodextrin is hydrophilic and the cavity forms a hydrophobic region due to the shielding effect of the C-H bond, so it can provide a hydrophobic binding site like an enzyme and act as a host to accommodate various suitable guests [76] , Porphyrins are often embedded in cyclodextrins.…”

Peroxidase‐mimicking activity of nanozymes‐loaded polymeric artificial organelles potentially active in acidic environment

“…Moreover, hemin has been linked to β-cyclodextrin (β-CD) to form an artificial enzyme with improved water solubility, where the inner space of β-CD acts as a hydrophobic pocket to host the substrates, and the high density of hydroxyl groups provides an electron-rich environment and facilitates the catalytic reaction. 13,15 Colloidal Hemin-based nanoparticle with intact catalytic performance and high cellular uptake properties have been reported. A hemin-conjugated nanoparticle is designed that can enter into cells, generate oxidative stress (ROS) inside the cells and induce autophagy.…”

“…This method involves a tedious synthesis and purification process. Moreover, hemin has been linked to β‐cyclodextrin (β‐CD) to form an artificial enzyme with improved water solubility, where the inner space of β‐CD acts as a hydrophobic pocket to host the substrates, and the high density of hydroxyl groups provides an electron‐rich environment and facilitates the catalytic reaction 13,15 . Colloidal Hemin‐based nanoparticle with intact catalytic performance and high cellular uptake properties have been reported.…”

Nanozyme Based on Porphyrinic Metal–Organic Framework for Electrocatalytic CO2 Reduction

“…They are: 1) to build homogeneous or heterogeneous catalysts whose structures mimic the active centers of natural enzymes; [6][7][8][9][10][11][12][13] and 2) to tune the second coordination sphere, by adjusting properties such as hydrophobicity, hydrogen bonding, and ionic interactions around active centers, to be similar to those found in nature. [14][15][16][17][18][19][20][21] Although the former approach has been extensively studied over the past few decades, the latter is becoming popular as an approach to drastically enhance catalytic performance through the introduction of substituents and hydrophobicity control, as exemplified by the O 2 reduction reaction (ORR) [22,23] and the CO 2 reduction reaction (CO 2 RR). [24][25][26][27] The importance of the second coordination sphere has been also highlighted through research on the zinc-containing enzyme, carbonic anhydrase, which catalyzes the reversible hydration of CO 2 and dehydration of HCO 3 À ; it was suggested that the hydrophobic region at the active center is responsible for CO 2 binding, which increases the catalytic activity.…”