Tritiated substrates at tracer levels were incubated with rat hepatocytes plus 10 mM L-lactate, and the yields of tritium in glucose and water, as well as the tritium distribution on C-6 and C-4 of glucose, determined. Substrates of cytosolic type A NAD-linked dehydrogenases showed some preferential labeling of C-6 of glucose (the pathway involving type A malate dehydrogenase), whereas substrates of cytosolic type B NAD-linked dehydrogenases showed some preferential labeling of C-4 of glucose (the pathway involving type B glyceraldehyde-3P dehydrogenase). The results found are consistent with a classical diffusion model of NADH metabolism, and are at odds with the Srivastava hypothesis (based on isolated enzyme studies) which indicated that direct transfer of NADH can occur between many NAD-linked enzymes but only when they are of opposite (A or B) specificity.
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http://dx.doi.org/10.1016/0003-9861(91)90079-x | DOI Listing |
Photosynth Res
January 2025
School of Biological Sciences, Washington State University, 406 Abelson Hall, Pullman, WA, 99164, USA.
Phosphoenolpyruvate (PEP) carboxylase (PEPC) has an anaplerotic role in central plant metabolism but also initiates the carbon concentrating mechanism during C photosynthesis. The C PEPC has different binding affinities (K) for PEP (K) and HCO (K), and allosteric regulation by glucose-6-phosphate (G6-P) compared to non-photosynthetic isoforms. These differences are linked to specific changes in amino acids within PEPC.
View Article and Find Full Text PDFACS Nano
December 2024
Key Laboratory of Imaging Diagnosis and Minimally Invasive Intervention Research, Imaging Diagnostic and Interventional Minimally Invasive Institute, The Fifth Affiliated Hospital of Wenzhou Medical University, No 289, Kuocang Road, Lishui 323000, China.
Fitoterapia
December 2024
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China. Electronic address:
Two unusual isosativene sesquiterpene derivatives, named dendronobilol A (1) and dendronobilside A (2), and two unusual sativene sesquiterpene derivatives, named dendronobilsides B (3) and C (4), had been isolated from the stems of Dendrobium nobile. The structures of all the compounds were established using spectroscopic methods and by comparison with literature data, and their absolute configurations were confirmed via single-crystal X-ray diffraction data and electronic circular dichroism (ECD) calculations. Dendronobilol A (1) and dendronobilside A (2) possessed a unique tricyclo[4.
View Article and Find Full Text PDFFitoterapia
December 2024
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, People's Republic of China. Electronic address:
The metabolites from the endophytic fungus Talaromyces malicola hosted in the gastrointestinal tract of the arthropods Armadillidium vulgare were investigated, and six undescribed fusicoccane diterpenoids, talarmalnoids A-F (1-6), along with three known analogs were isolated. Talarmalnoid C (3) was an unprecedented fusicoccane diterpenoid with two sugar units, i.e.
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