THE STUDY AND APPLICATION OF BIOMIMIC PEROXIDASE FERRIC 2-HYDROXY-1-NAPHTHALDEHYDE THIOSEMICARBAZONE (FE-III-HNT)

Ferric 2-hydroxy-1-naphthaldehyde thiosemicarbazone (Fe-III-HNT) has b een synthesized and used to mimic the active group of horseradish pero xidase (HRP). The catalytic characteristics of this mimic-enzyme catal yst in the oxidation reaction of ascorbic acid with hydrogen peroxide has been studied. The experimental results showed that this peroxidase model compound has similar catalytic activity that of HRP. The cataly tic activity of Fe-III-HNT has been compared with those of HRP and com mon mimic-enzymes, metalloporphyrins (e.g. metal tetrakis(sulphophenyl )porphyrin (Me-TPPS4)). Though the catalytic activity of Fe-III-HNT is 75% of that of HRP, it can be used as a new kind of mimic-enzyme cata lyst in determination of trace H2O2. By coupling this mimetic catalyti c reaction with the catalytic reaction of glucose oxidase, glucose can be determined indirectly. Under experimental conditions the linear re lationship between Delta A(265) and glucose concentration was in the r ange of 2.0-40.0 mu g ml(-1), The correlation coefficient (r) was 0.99 96. The R.S.D. (P = 0.05, n = 6) was 0.24%. The detection limit was de termined to be 0.238 mu g ml(-1). It was applied successfully to the d etermination of glucose in normal human and diabetic urine. The values of determination by the proposed method were compared with those of a routine method (enzymic glucose determination) applied in an hospital clinical laboratory. The agreement was very good. (C) 1998 Elsevier S cience B.V. All rights reserved.