1.
Highly sensitive colorimetric detection of glucose through glucose oxidase and Cu2+-catalyzed 3,3',5,5'-tetramethylbenzidine oxidation.
Li, X, Gao, L, Chen, Z
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 2019;:37-41
Abstract
We develop a glucose oxidase (GOx)-mediated strategy for detecting glucose based on oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB), which is generated from Cu2+-catalyzed 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 reaction, as colorimetric readout. The sensing system involves two processes: generation of H2O2 from GOx-catalyzed oxidation of glucose, and H2O2-induced the oxidization of TMB via the catalysis of Cu2+. The H2O2 formed by GOx-catalyzed oxidation of glucose oxidizes colorless TMB to blue oxTMB, thus enhancing the absorbance intensity at 670 nm. Therefore, we draw a conclusion that the enhancement in colorimetric signal relies directly on H2O2 concentration, which, in turn, depends on glucose concentration. This color change can be used not only for visual detection of glucose by naked eyes but for reliable glucose quantification in the range from 1 to 100 nM with a detection limit of 0.21 nM. The method possesses the following advantages: simple design, low experimental cost, and no any additional experimental equipment for heating, illuminating, or bubbling.
2.
Protein design and engineering of a de novo pathway for microbial production of 1,3-propanediol from glucose.
Chen, Z, Geng, F, Zeng, AP
Biotechnology journal. 2015;(2):284-9
Abstract
Protein engineering to expand the substrate spectrum of native enzymes opens new possibilities for bioproduction of valuable chemicals from non-natural pathways. No natural microorganism can directly use sugars to produce 1,3-propanediol (PDO). Here, we present a de novo route for the biosynthesis of PDO from sugar, which may overcome the mentioned limitations by expanding the homoserine synthesis pathway. The accomplishment of pathway from homoserine to PDO is achieved by protein engineering of glutamate dehydrogenase (GDH) and pyruvate decarboxylase to sequentially convert homoserine to 4-hydroxy-2-ketobutyrate and 3-hydroxypropionaldehyde. The latter is finally converted to PDO by using a native alcohol dehydrogenase. In this work, we report on experimental accomplishment of this non-natural pathway, especially by protein engineering of GDH for the key step of converting homoserine to 4-hydroxy-2-ketobutyrate. These results show the feasibility and significance of protein engineering for de novo pathway design and overproduction of desired industrial products.
3.
CD147 promotes reprogramming of glucose metabolism and cell proliferation in HCC cells by inhibiting the p53-dependent signaling pathway.
Huang, Q, Li, J, Xing, J, Li, W, Li, H, Ke, X, Zhang, J, Ren, T, Shang, Y, Yang, H, et al
Journal of hepatology. 2014;(4):859-66
Abstract
BACKGROUND & AIMS Cancer cells exhibit the reprogrammed metabolism characterized by high level of glycolysis even in the presence of oxygen. Aerobic glycolysis, known as the Warburg effect, supplies cancer cells with the substrates required for biomass generation. To date, several intracellular signaling mediators have been identified in metabolic regulation of cancer cells. However, it remains largely ambiguous how molecules on the cell surface are involved in regulation of cancer metabolism. METHODS In the current study, we established several HCC cell lines differing in their CD147 (a typical transmembrane glycoprotein) expression status by zinc-finger nuclease and RNAi techniques. Then, we systematically investigated the role of CD147 in the regulation of the Warburg effect in HCC cells and explored the underlying mechanism. RESULTS We found that CD147 significantly contributed to the reprogramming of glucose metabolism in HCC cells through a p53-dependent way. CD147 facilitated the cell surface expression of MCT1 and lactate export, which led to activation of the PI3K/Akt/MDM2 pathway and thus increased p53 degradation. The gain/loss-of-function studies demonstrated that while CD147 promoted glycolysis, mediated by p53-dependent upregulation of GLUT1 and activation of PFKL, it inhibited mitochondrial biogenesis and functions, mediated by p53-dependent downregulation of PGC1α, TFAM, and p53R2. Additionally, proliferation of HCC cells was suppressed by blocking CD147 and/or MCT1, which resulted in down-regulation of glucose metabolism. CONCLUSIONS We demonstrate that CD147 is a crucial regulator of glucose metabolism.
4.
Decoding Alzheimer's disease from perturbed cerebral glucose metabolism: implications for diagnostic and therapeutic strategies.
Chen, Z, Zhong, C
Progress in neurobiology. 2013;:21-43
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Abstract
Alzheimer's disease (AD) is an age-related devastating neurodegenerative disorder, which severely impacts on the global economic development and healthcare system. Though AD has been studied for more than 100 years since 1906, the exact cause(s) and pathogenic mechanism(s) remain to be clarified. Also, the efficient disease-modifying treatment and ideal diagnostic method for AD are unavailable. Perturbed cerebral glucose metabolism, an invariant pathophysiological feature of AD, may be a critical contributor to the pathogenesis of this disease. In this review, we firstly discussed the features of cerebral glucose metabolism in physiological and pathological conditions. Then, we further reviewed the contribution of glucose transportation abnormality and intracellular glucose catabolism dysfunction in AD pathophysiology, and proposed a hypothesis that multiple pathogenic cascades induced by impaired cerebral glucose metabolism could result in neuronal degeneration and consequently cognitive deficits in AD patients. Among these pathogenic processes, altered functional status of thiamine metabolism and brain insulin resistance are highly emphasized and characterized as major pathogenic mechanisms. Finally, considering the fact that AD patients exhibit cerebral glucose hypometabolism possibly due to impairments of insulin signaling and altered thiamine metabolism, we also discuss some potential possibilities to uncover diagnostic biomarkers for AD from abnormal glucose metabolism and to develop drugs targeting at repairing insulin signaling impairment and correcting thiamine metabolism abnormality. We conclude that glucose metabolism abnormality plays a critical role in AD pathophysiological alterations through the induction of multiple pathogenic factors such as oxidative stress, mitochondrial dysfunction, and so forth. To clarify the causes, pathogeneses and consequences of cerebral hypometabolism in AD will help break the bottleneck of current AD study in finding ideal diagnostic biomarker and disease-modifying therapy.
5.
Glucose biosensor based on three dimensional ordered macroporous self-doped polyaniline/Prussian blue bicomponent film.
Chen, X, Chen, Z, Tian, R, Yan, W, Yao, C
Analytica chimica acta. 2012;:94-100
Abstract
In this paper, a three dimensional ordered macroporous self-doped polyaniline/Prussian blue (3DOM SPAN/PB) bicomponent film was fabricated via the inverted crystal template technique using step-by-step electrodeposition. In this bicomponent film, PB not only acted as a redox mediator, but also presented increased stability in neutral or weak alkaline solution by the protection of SPAN layer on the top. A novel glucose biosensor was fabricated based on the large active surface area and excellent conductivity possessed by the 3DOM SPAN/PB film. The applying experimental conditions of the glucose biosensor have been optimized. Under the optimal conditions, the biosensor showed a wide linear range over three orders of magnitude in glucose concentrations (from 2 to 1600 μM) and a low detection limit of 0.4 μM. Moreover, the biosensor exhibited short response time, high selectivity and excellent operation stability, which can be applied to detect the blood sugar in real samples without any pretreatment.