Detection of 25-Hydroxyvitamin D3 with an Enzyme modified Electrode
- *Corresponding Author:
- Alan C West
Department of Chemical Engineering
Columbia University, New York, USA
E-mail: [email protected] edu
Received Date: November 17, 2015 Accepted Date: December 12, 2015 Published Date: January 02, 2016
Citation: Ozbakir HF, Sambade DA, Majumdar S, Linday LA, Banta S, et al. (2016) Detection of 25-Hydroxyvitamin D3 with an Enzyme modified Electrode. J Biosens Bioelectron 7:193. doi:10.4172/2155-6210.1000193
Copyright: © 2016 Ozbakir HF, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Since testing for circulating vitamin D concentrations is relatively expensive and time consuming, rapid means of measurement are desired. As a step towards this goal, enzyme-modified electrodes responsive to 25-hydroxyvitamin D3 (25(OH)D3) have been developed. To make the enzyme, a synthetic gene encoding a human cytochrome P450 27B1 (CYP27B1) enzyme, which is a mitochondrial type heme-thiolate monooxygenase that converts 25(OH)D3 into 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), was expressed and purified. The CYP27B1 enzyme was combined with NADPH-adrenodoxin reductase (ADR) and adrenodoxin (ADX) and activity was characterized using liquid chromatography mass spectrometry (LC-MS/MS). It was found that dihydroxyvitamin D3 isomers were produced in addition to 1,25(OH)2D3. The enzyme was immobilized on glassy carbon electrodes using pH-adjusted Nafion® along with cobalt sepulchrate trichloride (Co(sep)3+) as a redox mediator and electrode performance was characterized using cyclic and square wave voltammetry. The results demonstrate detection of 25(OH)D3 in buffer within the physiological range (5-200 ng/ml).