Temperature modulated solubility and activity alteration for oligo-(N-isopropylacrylamide)-iron tetrasulfonatophthalocyanine conjugates as a new mimetic peroxidase

Iron tetrasulfonatophthalocyanine (FeTSPc) was covalently bound to the term inus of a temperature sensitive oligomer, oligo-N-isopropylacrylamide (ONIP AAm), to form a new mimetic enzyme (ONIPAAm-FeTSPc) to; mimic the peroxidas e activity of horseradish peroxidase. This FeTSPc-based mimetic enzyme exhi bits a lower critical solution temperature (LCST) of 32 degrees C in neutra l solution. It precipitates from water above the LCST and redissolves when the solution temperature is lowered below the LCST. The peroxidase activity of this mimetic enzyme was studied based on its catalytic effect on the re action of p-hydroxyphenylpropionic acid and H2O2 The results show that the peroxidase activity of the new mimetic enzyme is higher than that of the fr ee FeTSPc. The possibility of its application in the analytical field was a lso tested by the determination of H2O2 and ONIPAAm-FeTSPc; the detection l imits are 8.2 x 10(-9) and 1.7 x 10(-9) mol L-1, respectively.