Putrescine N-methyltransferase (PMT) catalyses S-adenosylmethionine (SAM) dependent methylation of the diamine putrescine. The product N-methylputrescine is the first specific metabolite on the route to nicotine, tropane, and nortropane alkaloids. PMT cDNA sequences were cloned from tobacco species and other Solanaceae, also from nortropane-forming Convolvulaceae and enzyme proteins were synthesised in Escherichia coli. PMT activity was measured by HPLC separation of polyamine derivatives and by an enzyme-coupled colorimetric assay using S-adenosylhomocysteine. PMT cDNA sequences resemble those of plant spermidine synthases (putrescine aminopropyltransferases) and display little similarity to other plant methyltransferases. PMT is likely to have evolved from the ubiquitous enzyme spermidine synthase. PMT and spermidine synthase proteins share the same overall protein structure; they bind the same substrate putrescine and similar co-substrates, SAM and decarboxylated S-adenosylmethionine. The active sites of both proteins, however, were shaped differentially in the course of evolution. Phylogenetic analysis of both enzyme groups from plants revealed a deep bifurcation and confirmed an early descent of PMT from spermidine synthase in the course of angiosperm development.
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http://dx.doi.org/10.1016/j.phytochem.2009.06.012 | DOI Listing |
Purpose: Understanding the molecular mechanisms of adaptive regulation in the tumor microenvironment is crucial for precision therapy in hepatocellular carcinoma (HCC). We hypothesized that cargo proteins carried by extracellular vesicles (EVs) released in a hypoxic microenvironment might promote HCC progression by remodeling tumor-associated macrophages (TAMs).
Methods: EV protein analysis by label-free proteomics mass spectrometry of HCC cell lines of different tumor grades was performed.
In Silico Pharmacol
December 2024
Laboratory of Cell and Molecular Biology, Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019 India.
Visceral Leishmaniasis, caused by is the second most deadly parasitic disease, causing over 65,000 deaths annually. Synthetic drugs available in the market, to combat this disease, have numerous side effects. In this backdrop, we aim to find safer antileishmanial alternatives with minimal side effects from mushrooms, which harbour various secondary metabolites with promising efficacy.
View Article and Find Full Text PDFGut Microbes
December 2024
Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
Enteropathogenic (EPEC) is a bacterium that causes attaching/effacing (A/E) lesions and serious diarrheal disease, a major health issue in developing countries. EPEC pathogenicity results from the effect of virulence factors and dysregulation of host responses. Polyamines, including spermidine, play a major role in intestinal homeostasis.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Faculty of Science and Engineering, Department of Biology, Konan University, Kobe, Japan; Institute of Integrative Neurobiology, Konan University, Kobe, Japan. Electronic address:
Phosphate (Pi) homeostasis at the cellular level is crucial, requiring coordinated Pi uptake, storage, and export. However, the regulatory mechanisms, particularly those governing Pi export, remain elusive, despite their relevance to human diseases like primary familial brain calcification. While Xpr1, conserved across eukaryotes, is the only known Pi exporter, the existence of additional Pi exporting factors is evident; however, these factors have been poorly characterized.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
National Key Laboratory for Tropical Crop Breeding, School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China. Electronic address:
The vanadium (V) toxicity predominantly is the primary limitation in restraining pepper growth. The silicon (Si) in pepper plants induced the transcript level of the polyamines metabolism pathway genes, including the arginase (CbARG), ornithine decarboxylase (CbODC), arginine decarboxylase (CbADC), N-carbamoylputrescine amidase (CbNCA), Spermidine synthase (CbSPDS), copper binding diamine oxidase (CbCuAO) to overcome the V toxicity. The polyamines, including the Spm, Spd, and Put, induced with Si about 41.
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