TY  - JOUR
A1  - Bistolas, Nikitas
A1  - Wollenberger, Ursula
A1  - Jung, Christiane
A1  - Scheller, Frieder W.
T1  - Cytochrome P450 biosensors : a review
N2  - Cytochrome P450 (CYP) is a large family of enzymes containing heme as the active site. Since their discovery and the elucidation of their structure, they have attracted the interest of scientist for many years, particularly due to their catalytic abilities. Since the late 1970s attempts have concentrated on the construction and development of electrochemical sensors. Although sensors based on mediated electron transfer have also been constructed, the direct electron transfer approach has attracted most of the interest. This has enabled the investigation of the electrochemical properties of the various isoforms of CYP. Furthermore, CYP utilized to construct biosensors for the determination of substrates important in environmental monitoring, pharmaceutical industry and clinical practice. (c) 2004 Elsevier B. V. All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Liu, Songqin
A1  - Wollenberger, Ursula
A1  - Halamek, Jan
A1  - Leupold, Eik
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Scheller, Frieder W.
T1  - Affinity interaction betwen phenylboronic acid-carrying self-assembled monolayers and FAD or HRP
N2  - A method is provided for the recognition of glycated molecules based on their binding affinities to boronate- carrying monolayers. The affinity interaction of flavin adenine dinucleotide (FAD) and horseradish peroxidase (HRP) with phenylboronic acid monolayers on gold was investigated by using voltammetric and microgravimetric methods. Conjugates of 3-aminopherrylboronic acid and 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) or 11-mercaptoundecanoic acid were prepared and self-assembled on gold surfaces to generate monolayers. FAD is bound to this modified sur-face and recognized by a pair of redox peaks with a formal potential of -0.433 V in a 0.1 m phosphate buffer solution, pH 6.5. Upon addition of a sugar to the buffer, the bound FAD could be replaced, indicating that the binding is reversible. Voltammetric, mass measurements, and photometric activity assays show that the HRP can also be bound to the interface. This binding is reversible, and HRP can be replaced by sorbitol or removed in acidic solution. The effects of pH, incubation time, and concentration of H2O2 were studied by comparing the catalytic reduction of H2O2 in the presence of the electron-donor thionine. The catalytic current of the HRP-loaded electrode was proportional to HRP concentrations in the incubation solution in the range between 5 mu g mL(-1) and 0.4 mg mL(-1) with a linear slope of 3.34 mu A mL mg(-1) and a correlation coefficient of 0.9945
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Bistolas, Nikitas
A1  - Liu, Songqin
A1  - Jänchen, Michael
A1  - Katterle, Martin
A1  - Wollenberger, Ursula
T1  - Thirty years of haemoglobin electrochemistry
N2  - Electrochemical investigations of the blood oxygen carrier protein include both mediated and direct electron transfer. The reaction of haemoglobin (Hb) with typical mediators, e.g., ferricyanide, can be quantified by measuring the produced ferrocyanide which is equivalent to the Hb concentration. Immobilization of the mediator within the electrode body allows reagentless electrochemical measuring of Hb. On the other hand, entrapment of the protein within layers of polyclectrolytes, lipids, nanoparticles of clay or gold leads to a fast heterogeneous electron exchange of the partially denatured Hb. (c) 2005 Elsevier B.V. All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Lisdat, Fred
A1  - Wollenberger, Ursula
T1  - Application of electrically contacted enzymes for biosensors
Y1  - 2005
SN  - 3-527- 30690-0
ER  - 
TY  - THES
A1  - Wollenberger, Ursula
T1  - Kopplung von Biomolekülen mit Elektroden : von Bioelektrochemie zur Biosensorik
Y1  - 2005
CY  - Potsdam
ER  -