Resumo (EN)
Introduction – Partial purificated extract of stunded banana (Musa acumunata), the best source of enzyme Poliphenol oxidase29 (PPO) [EC.1.14.18.1] was studied as biocatalitic material to the aerobic oxidation of phenolics substrates using an amperometry biosensor with PPO immobilized. Material and Methods – The extraction of PPO was studied in the source29, the partial purification of this crude extract using ammonium sulphate (40%), that precipitate the enzyme excess presents in this extract with posterior dialysis27. After it was determinated the total activity and proteins in the two extracts. An amperometric biosensor was builded using 50 U of PPO proceeding of purificated partial extract of stunded banana; immobilized on a Teflon membrane (Celgard 2400), with the use of the reagent glutaraldeyde 2,5% m/v. After drying, this enzymatic membrane was copled in the extremity of an oxygen electrode. This biosensor was used in the determination of phenolics in urine samples of persons that use drugs, metabolizing phenols by amperometry and by spectrophotometry. Results – In the urine samples, was possible to notice that persons that use L- Dopa shows greather quantity of phenols than persons that use amphetamines. Conclusions – The percentage of error in the samples studied was minor that 3%, using the crude extract28 and purificated partialment, using the spectrophotometric standard method40, showing the efficiency of the amperometric method used with or without the enzymatic purification.