期刊
BIOSENSORS & BIOELECTRONICS
卷 41, 期 -, 页码 563-568出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2012.09.024
关键词
G-quadruplex; Cupric ion; Fluorescence; Histidine detection; Cysteine detection
类别
资金
- National Natural Science Foundation of China [21190040, 21105095]
- 973 project [2010CB933600, 2009CB930100]
Histidine and cysteine detection is critically important since an abnormal level of histidine or cysteine is an indicator for many diseases. In this paper, we demonstrated a novel label-free, G-quadruplex-based approach for simultaneous detection of histidine and cysteine. The present assay is based on the highly specific interaction among amino acids (histidine or cysteine), Cu2+ and NMM/G-4 (NMM: N-methylmesoporphyrin IX; G-4: G-quadruplex). The fluorescence intensity of NMM was dramatically enhanced in the presence of G-quadruplex formed from 24GT, which can be effectively quenched by cupric ion (Cu2+) due to the chelation of Cu2+ by NMM as well as the unfolding of G-quadruplex by Cu2+. The presence of histidine or cysteine will disturb the interaction between Cu2+ and NMM/G-4 because of the strong binding affinity of Cu2+ to the imidazole group of histidine or the interaction of Cu2+ with thiol group in cysteine, leading to distinct fluorescence emission intensity. High selectivity is conferred by the use of cysteine-masking agent N-ethylmaleimide (NEM), which helps to discriminate histidine from cysteine. At last, a novel and simple approach was developed to determine each precise concentration of histidine and cysteine according to the different response of the system with and without NEM. Importantly, histidine can be also detected even in the presence of a large amount of other amino acids. A detection limit as low as 3 nM for histidine and 5 nM for cysteine was obtained by practical measurement rather than conventional calculation (S/N=3), confirming the high sensitivity of the present approach. Meanwhile, this sensing protocol can determine histidine and cysteine in diluted biological samples such as urine, exhibiting great potential to meet the need of practical application. (C) 2012 Published by Elsevier B.V.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据