Protocols in Current Issue
    Characterising Plant Deubiquitinases with in vitro Activity-based Labelling and Ubiquitin Chain Disassembly Assays
    Authors:  Michael J. Skelly and Steven H. Spoel, date: 05/05/2021, view: 424, Q&A: 0

    Post-translational modification of proteins by ubiquitin is an essential cellular signaling mechanism in all eukaryotes. Ubiquitin is removed from target proteins by a wide range of deubiquitinase (DUB) enzymes with different activities and substrate specificities. Understanding how DUBs function in vitro is a vital first step to uncovering their

    In vitro Reconstitution Assays of Arabidopsis 20S Proteasome
    Authors:  Yanjun Li, Di Sun, Xingxing Yan, Zhiye Wang and Xiuren Zhang, date: 04/05/2021, view: 471, Q&A: 0

    The majority of cellular proteins are degraded by the 26S proteasome in eukaryotes. However, intrinsically disordered proteins (IDPs), which contain large portions of unstructured regions and are inherently unstable, are degraded via the ubiquitin-independent 20S proteasome. Emerging evidence indicates that plant IDP homeostasis may also be

    Quantitative Measurement of Mucolytic Enzymes in Fecal Samples
    Authors:  Shahanshah Khan and Hasan Zaki, date: 03/20/2021, view: 1052, Q&A: 0

    The mucus layer in the gastrointestinal tract covers the apical surface of intestinal epithelial cells, protecting the mucosal tissue from enteric pathogen and commensal microorganisms. The mucus is primarily composed of glycosylated protein called mucins, which are produced by goblet cells, a type of columnar epithelial cells in the intestinal

    Polyamine Transport Assay Using Reconstituted Yeast Membranes
    Authors:  Sarah van Veen, Shaun Martin, Marleen Schuermans and Peter Vangheluwe, date: 01/20/2021, view: 1235, Q&A: 0

    ATP13A2/PARK9 is a late endo-/lysosomal P5B transport ATPase that is associated with several neurodegenerative disorders. We recently characterized ATP13A2 as a lysosomal polyamine exporter, which sheds light on the molecular identity of the unknown mammalian polyamine transport system. Here, we describe step by step a protocol to measure

    Assessment of Diadenylate Cyclase and c-di-AMP-phosphodiesterase Activities Using Thin-layer and Ion Exchange Chromatography
    Authors:  Andreas Latoscha, David Jan Drexler, Gregor Witte and Natalia Tschowri, date: 01/05/2021, view: 887, Q&A: 0

    All living cells use cyclic nucleotides as second messengers for signal sensing and transduction. Cyclic di-3′,5′-adenosine monophosphate (c-di-AMP) is primarily involved in the control of bacterial and euryarcheal osmoadaptation and is produced by diadenylate cyclases from two molecules of ATP. Specific phosphodiesterases hydrolyze

    Non-radioactive Assay to Determine Product Profile of Short-chain Isoprenyl Diphosphate Synthases
    Authors:  Avanish Rai and Dinesh A. Nagegowda, date: 01/05/2021, view: 859, Q&A: 0
    [Abstract] Isoprenoids represent the largest class of metabolites with amazing diversities in structure and function. They are involved in protecting plants against pathogens or herbivores or involved in attracting pollinators. Isoprenoids are derived from geranyl diphosphate (GPP; C10), farnesyl diphosphate (FPP; C15), geranylgeranyl ...
    The ATPase Activity of Escherichia coli Expressed AAA+-ATPase Protein
    Authors:  Amita Kaundal, Vemanna S. Ramu and Kirankumar S. Mysore, date: 08/05/2020, view: 1650, Q&A: 0
    [Abstract] ATPases are the enzymes that breakdown ATP to ADP and release inorganic phosphate (Pi). Here we provide a detailed protocol to determine the ATPase activity of a recombinant AAA+-ATPase protein (GENERAL CONTROL NON-REPRESSIBLE-4 [GCN4]) by spectrophotometric absorption at 360 nm to measure the accumulated inorganic phosphate. In ...
    Quantification of Protein Kinase A (PKA) Activity by An in vitro Radioactive Assay Using the Mouse Sperm Derived Enzyme
    Authors:  Cintia Stival, Carolina Baro Graf, Pablo E. Visconti and Dario Krapf, date: 06/20/2020, view: 1987, Q&A: 0
    [Abstract] In order to acquire fertilizing potential, mammalian sperm must undergo a process known as capacitation, which relies on the early activation of Protein Kinase A (PKA). Frequently, PKA activity is assessed in whole-cell experiments by analyzing the phosphorylation status of its substrates in a western-blot. This technique ...
    Preparation of HeLa Total Membranes and Assay of Lipid-inhibition of Serine Palmitoyltransferase Activity
    [Abstract] Serine palmitoyltranferase (SPT) is a pyridoxal 5′ phosphate (PLP)-dependent enzyme that catalyzes the first and rate-limiting step of de novo synthesis of sphingolipids. SPT activity is homeostatically regulated in response to increased levels of sphingolipids. This homeostatic regulation of SPT is mediated through small ER membrane ...
    A Sensitive Coupled Enzyme Assay for Measuring Kinase and ATPase Kinetics Using ADP-Specific Hexokinase
    Authors:  Ciaran R. McFarlane and James W. Murray, date: 05/05/2020, view: 2889, Q&A: 0
    [Abstract] Kinases and ATPases perform essential biological functions in metabolism and regulation. Activity of these enzymes is commonly measured by coupling ATP consumption to the synthesis of a detectable product. For most assay systems the ATP concentration during the reaction is unknown, compromising the precision of the assay.

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