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Exfoliated Nanosheets of a Cu II Coordination Polymer Modulate Enzyme Activity of α‐Chymotrypsin
Author(s) -
Sarkar Koushik,
Dastidar Parthasarathi
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201802376
Subject(s) - substrate (aquarium) , enzyme , histidine , active site , chemistry , active center , coordination polymer , stereochemistry , chymotrypsin , ionic bonding , enzyme assay , nanosheet , polymer , materials science , polymer chemistry , organic chemistry , biology , ion , ecology , trypsin
A 2D coordination polymer derived from 5‐azidoisophthalic acid ( AIA ) and Cu(NO 3 ) 2 was designed with the aim of modulating the activity of a digestive enzyme α‐chymotrypsin ( ChT ). The coordination polymer namely {[Cu 0.5 (μ‐AIA) 0.5 (H 2 O)]⋅2 H 2 O} α ( CP1 ) was successfully synthesized and fully characterized by single‐crystal X‐ray diffraction (SXRD). An exfoliated nanosheet (ENS) of CP1 was readily produced by overnight stirring of hand‐ground CP1 crystals dispersed in DMSO. ENS(CP1) was demonstrated to be acting as an inhibitor of ChT ; as much as ≈97 % inhibition of ChT was achieved with 100 μ m of ENS(CP1) using N ‐succinyl‐ l ‐phenylalanine‐ p ‐nitroanilide (SPNA) as substrate. Enzyme kinetics data revealed that the inhibition of ChT followed a competitive pathway. An enzyme assay under varying ionic strength and varying concentration of free histidine revealed that the active site His‐57 participated in coordination with the Cu II metal center of ENS(CP1) thereby preventing the substrate (SPNA) from binding with the enzyme resulting in efficient inhibition.