The fabrication and notably improved performance of composite electrodes based on the nanocomposite of diphenylalanine peptide-covered multiwalled carbon nanotube (PP-MWCNT) is described. The synthesis of the nanocomposite of PP-MWCNT is a self-assembly process of diphenylalanine peptide (PP) along carbon nanotube (MWCNT) via aromatic stacking interaction combined with hydrogen bond of diphenylalanine peptide. PP-MWCNT modified electrode was fabricated by a simple casting method, and studied with cyclic voltammetry (CV) and chronoamperometry. PP-MWCNT modified electrode showed a high, direct and unmediated response to beta-reduced coenzyme nicotinamide adenine dinucleotide (NADH) at a potential of 0.600 V (vs. SCE), which had reduced the overvoltage of NADH oxidation by 0.200 V in comparison with the bare electrode. Furthermore, the current response of NADH at PP-MWCNT modified electrode is about five times higher than that of the bare electrode. Thus, PP-MWCNT provides a new candidate for fabrication of biosensor based on beta-coenzyme nicotinamide adenine dinucleotide (NAD(+))-dependent dehydrogenases. Herein, an ethanol biosensor was prepared by crosslinking ethanol dehydrogenase (ADH), bovine serum albumin (BSA) and PP-MWCNT onto the electrode. The ethanol biosensor exhibited a good linearity ranged from 30 mu M to 700 mu M with a high sensitivity of 30.00 nA/mu M cm(-2) and with a low detection limit of 12 mu M. (C) 2010 Elsevier B.V. All rights reserved.