The effects of three potential irreversible inhibitors of gamma-aminobutyrate aminotransferase from Pseudomonas fluorescens were studied in order to throw more light on the nature of the active site of the enzyme. The thiol group reagent mercuric chloride inactivated the enzyme in a concentration-dependent manner. Inhibition kinetics were consistent with a simple bimolecular reaction. The second-order rate constant was 4.2 x 10(3) +/- 0.61 M-1 sec-1. In contrast to either of the substrates, the cofactor pyridoxal 5'-phosphate could protect the enzyme from the inhibition, suggesting cysteinyl residues are important for cofactor binding at the active site. p-Chloromercuribenzoic acid produced a similar inactivation of the enzyme. 4-Amino-2-fluorobutanoic acid also inhibited enzymic activity but in this case the inhibition was reversible and competitive with respect to gamma-aminobutyric acid (GABA). The inhibitor constant (Ki) was 0.83 +/- 0.44 mM. We found no evidence that this fluorinated analogue of GABA could act as a substrate for the enzyme.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1080/15216549800203542 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modulation of the Second-Beyond Coordination Structure in Single-Atom Electrocatalysts for Confirmed Promotion of Ammonia Synthesis.
J Am Chem Soc
January 2025
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Although microenvironments surrounding single-atom catalysts (SACs) have been widely demonstrated to have a remarkable effect on their catalytic performances, it remains unclear whether the local structure beyond the secondary coordination shells works as well or not. Herein, we employed a series of metal-organic frameworks (MOFs) with well-defined and tunable second-beyond coordination spheres as model SAC electrocatalysts to discuss the influence of long-distance structure on the ammonia synthesis from nitrate, which were synthesized and denoted as Cu-NDI-X (X = NMe, H, F). It is first experimentally confirmed that the remote substitution of function groups beyond the secondary coordination sphere can remarkably affect the activity of ammonia synthesis.
View Article and Find Full Text PDFDiagnosis and Treatment Options for Cirrhosis With Unexplained Upper Gastrointestinal Bleeding: An Observational Study Based on Endoscopic Ultrasonography.
Surg Laparosc Endosc Percutan Tech
January 2025
Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, Key Laboratory of Digestive Diseases of Anhui Province, Hefei, Anhui, China.
Objective: To investigate the role of endoscopic ultrasonography (EUS) in the diagnosis and treatment of upper gastrointestinal bleeding of unknown origin in liver cirrhosis, focusing on patients with recurrent treatment of esophageal and gastric varices who failed to identify the bleeding site under direct endoscopy.
Background: Esophagogastric variceal bleeding is one of the severe complications of decompensated liver cirrhosis, and serial endoscopic therapy can improve the long-term quality of life of patients. Most acute bleeding can be detected under direct endoscopy with thrombus or active bleeding, but there are still some patients with recurrent bleeding after repeated treatments, and it is difficult to find the bleeding site, especially in gastric variceal bleeding.
Identification of Natural Terpenoid Compounds as Potential Inhibitors of Nucleoprotein of Influenza A Virus using in silico Approach: ADMET, Molecular Docking, and Molecular Dynamic Simulation.
Med Chem
January 2025
Laboratory of Biotechnology and Natural Resources Valorization, Faculty of Sciences of Agadir, Ibn Zohr University, Agadir, Morocco.
Background: We continue to struggle with the prevention and treatment of the influenza virus. The 2009 swine flu pandemic, caused by the H1N1 strain of influenza A, resulted in numerous fatalities. The threat of influenza remains a significant concern for global health, and the development of novel drugs targeting these viruses is highly desirable.
View Article and Find Full Text PDFInduction of Nanoscale Magnetic Ordering in Non-Ferrous Layered Double Hydroxides: Stabilizing Spintronic Electrocatalysis.
Small
January 2025
School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
Inducing magnetic ordering in a non-ferrous layered double hydroxides (LDHs) instigates higher spin polarization, which leads to enhanced efficiency during oxygen evolution reaction (OER). In nano-sized magnetic materials, the concept of elongated grains drives domain alignment under the application of an external magnetic field. Hence, near the solid electrode interface, modified magnetohydrodynamics (MHD) positively impacts the electrocatalytic ability of non-ferrous nanocatalysts.
View Article and Find Full Text PDFUnveiling the Dual Active Sites of Ni/Co(OH)-Ru Heterointerface for Robust Electrocatalytic Alkaline Seawater Splitting.
Small
January 2025
Department of Chemistry, School of Forensic Medicine, China Medical University, Shenyang, 110122, P. R. China.
Constructing bifunctional electrocatalysts through the synergistic effect of diverse metal sites is crucial for achieving high-efficiency and steady overall water splitting. Herein, a "dual-HER/OER-sites-in-one" strategy is proposed to regulate dominant active sites, wherein Ni/Co(OH)-Ru heterogeneous catalysts formed on nickel foam (NF) demonstrate remarkable catalytic activity for oxygen evolution reaction (OER) as well as hydrogen evolution reaction (HER). Meanwhile, the potentials@10 mA cm of Ni/Co(OH)-Ru@NF for overall alkaline water and seawater splitting are only 1.
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!