The apparent Michaelis constant, K(M), for glutamate oxidase (GluOx) immobilised on Pt electrodes increased systematically with enzyme loading. The effect was due, at least in part, to electrostatic repulsion between neighbouring oxidase molecules and the anionic substrate, glutamate (Glu). This understanding has allowed us to increase the Glu sensitivity of GluOx-based amperometric biosensors in the linear response region (100+/-11 nA cm(-2)microM(-1) at pH 7.4; SD, n=23) by incorporating a polycation (polyethyleneimine, PEI) to counterbalance the polyanionic protein. Differences in the behaviour of glucose biosensors of a similar configuration highlight a limitation of using glucose oxidase as a model enzyme in biosensor design.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/b511643k | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Primary Roles of Branched Chain Amino Acids (BCAAs) and Their Metabolism in Physiology and Metabolic Disorders.
Molecules
December 2024
Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585, Japan.
Leucine, isoleucine, and valine are collectively known as branched chain amino acids (BCAAs) and are often discussed in the same physiological and pathological situations. The two consecutive initial reactions of BCAA catabolism are catalyzed by the common enzymes referred to as branched chain aminotransferase (BCAT) and branched chain α-keto acid dehydrogenase (BCKDH). BCAT transfers the amino group of BCAAs to 2-ketoglutarate, which results in corresponding branched chain 2-keto acids (BCKAs) and glutamate.
View Article and Find Full Text PDFα-Ketoisocaproic Acid Disrupts Mitochondrial Bioenergetics in the Brain of Neonate Rats: Molecular Modeling Studies of α-ketoglutarate Dehydrogenase Subunits Inhibition.
Neurochem Res
January 2025
Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Brain accumulation of the branched-chain α-keto acids α-ketoisocaproic acid (KIC), α-keto-β-methylvaleric acid (KMV), and α-ketoisovaleric acid (KIV) occurs in maple syrup urine disease (MSUD), an inherited intoxicating metabolic disorder caused by defects of the branched-chain α-keto acid dehydrogenase complex. Patients commonly suffer life-threatening acute encephalopathy in the newborn period and develop chronic neurological sequelae of still undefined pathogenesis. Therefore, this work investigated the in vitro influence of pathological concentrations of KIC (5 mM), KMV (1 mM), and KIV (1 mM) on mitochondrial bioenergetics in the cerebral cortex of neonate (one-day-old) rats.
View Article and Find Full Text PDFAngelica gigas Nakai (Korean Dang-gui) Root Alcoholic Extracts in Health Promotion and Disease Therapy - active Phytochemicals and In Vivo Molecular Targets.
Pharm Res
January 2025
Penn State Cancer Institute, Pennsylvania State University, Hershey, PA, 17033, USA.
Angelica gigas Nakai (AGN) root is a medicinal herbal widely used in traditional medicine in Korea. AGN root ethanolic extracts have been marketed as dietary supplements in the United States for memory health and pain management. We have recently reviewed the pharmacokinetics (PK) and first-pass hepatic metabolism of ingested AGN supplements in humans for the signature pyranocoumarins decursin (D, C 1x), decursinol angelate (DA, C ~ 10x) and their common botanical precursor and hepatic metabolite decursinol (DOH, C ~ 1000x).
View Article and Find Full Text PDFUntargeted Metabolomics Reveals Metabolic Link Between Histone H3K27 Demethylase UTX and Neurodevelopment.
J Cell Mol Med
January 2025
Department of Pharmacy, Chongqing Health Center for Women and Children, Women and Children's Hospital of Chongqing Medical University, Chongqing, China.
Ubiquitously transcribed tetratricopeptide repeat on chromosome X (UTX) is a chromatin modifier responsible for regulating the demethylation of histone H3 lysine 27 trimethylation (H3K27me3), which is crucial for human neurodevelopment. To date, the impact of UTX on neurodevelopment remains elusive. Therefore, this study aimed to investigate the potential molecular mechanisms underlying the effects of UTX on neurodevelopment through untargeted metabolomics based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
View Article and Find Full Text PDFAmperometric Biosensor Based on Glutamate Oxidase to Determine Ast Activity.
Sensors (Basel)
December 2024
Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 03680 Kyiv, Ukraine.
This work presents the development of an amperometric biosensor for detecting aspartate aminotransferase (AST) activity in biological fluids using a platinum disk electrode as the working transducer. Optimal concentrations of substrates (aspartate, α-ketoglutarate) and the coenzyme (pyridoxal phosphate) were determined to ensure efficient biosensor operation. A semi-permeable poly-m-phenylenediamine membrane was applied to enhance selectivity against electroactive interferents.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!