Artificial Peptidase with an Active Site Comprising a Cu(II) Center and a Proximal Guanidinium Ion. A Carboxypeptidase A Analogue

Abstract

An immobile artificial metallopeptidase having a well-defined active site was constructed on the backbone of cross-linked polystyrene by adjoining a guanidinium moiety to the Cu(II) complex of a tetraaza ligand. The catalyst (CABP) and intermediate polymers were characterized by elemental analysis, IR, inductively coupled plasma measurement, electron probe microanalysis, test for primary amines, binding of Cu(II) ion, and complexation of p-nitrobenzoate ion. CABP effectively catalyzed amide hydrolysis of carboxyl-containing N-acyl amino acids. The catalytic rate of CABP in the hydrolysis of unactivated amides was comparable to that of the catalytic antibody with the highest peptidase activity reported to date. It is proposed that the guanidinium moiety of CABP recognizes the carboxylate anion of the substrate whereas the Cu(II) center participates in the cleavage of the amide bond of the complexed substrate. Several characteristic features of carboxypeptidase A were reproduced by CABP: catalytic action of the metal ion, participation of guanidinium in substrate recognition, hydrolysis of small unactivated amides, and substrate selectivity toward amide bonds adjacent to a carboxylate group.

Peptide‐ or Protein‐Cleaving Agents Based on Metal Complexes

“…The active site of BB was constructed on the surface of partially chloromethylated cross-linked polystyrene (PCPS) (112). Here, the active site was chiral since L-arginine was used to introduce the guanidinium portion.…”

Carbon Dots/Cu2O Composite with Intrinsic High Protease‐Like Activity for Hydrolysis of Proteins under Physiological Conditions

“…Most reported artificial mimics proteases possess hydrolysis activity under alkaline and high‐temperature conditions, which greatly limits their applications in biological systems where a near neutral pH is required . In the only study so far published, Cu([9]aneN 3 )Cl 2 hydrolyzed BSA into two discrete polypeptides of ≈27 and 40 kDa after 7 d at near neutral pH and 50 °C .…”

“…However, the proteolytic activity of that synzyme toward other protein substrates was insignificant, suggesting its narrow substrate selectivity . An artificial metalloprotease that selectively hydrolyzes carboxyl‐containing amides was prepared by using a guanidinium moiety positioned near a Cu 2+ center on the surface of cross‐linked polystyrene . Artificial active sites comprising the Cu(II) complex of cyclen (Cu(II)Cyc) and aldehyde group were synthesized on a cross‐linked polystyrene to design artificial proteases .…”

Ternary complexes of cobalt cysteinylglycine with histidylserine and histidylphenylalanine-stabilities and DNA cleavage properties

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] A survey of literature reveals that the most efficient cleavage agents involving hydrolytic mechanism happens to be the mononuclear complexes 15-22 as compared to the dinuclear, 23-27 trinuclear 28-31 and multinuclear complexes. 32,33 Enhancement of rate constants in the range of 0⋅09-0⋅25 h -1 for DNA hydrolysis by metal complexes are considered impressive 34,35 even though, they are still far from the rate enhancements produced by natural enzymes (between 40 and 1⋅4 × 10 4 h -1 ). 36,37 Recently, attention has been focused towards the development of cobalt complexes as DNA cleavage agents.…”