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Mite allergens
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Enrique Fernández-Caldas, Leonardo Puerta, Luis Caraballo, Victor Iraola, Richard F. Lockey
Blo t 19 is a 7 kDa allergen showing homology to an antimicrobial peptide. The structure of a 68-amino-acid peptide has been elucidated by nuclear magnetic resonance (NMR) spectroscopy and registered in the Protein Data Bank database (code 2MFJ). It has a 10% frequency of IgE reactivity in mite-allergic subjects [117]. The Der f 20 is an arginine kinase [118]. It has similarities with arginine kinase from D. pteronyssinus and Aleuroglyphus ovatus. Western-blot and ELISA studies showed IgE-binding capacity of 66.7% in the sera from dust mite-allergic patients from Guangzhou, China [119,120].
Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
Equation 25 in Section I.A implies that proteins substituted with more iodine are likely to be more heterogeneous in regard to the distribution of the label. Therefore, I/P values should be kept as low as possible. However, this does not mean that carrier-free iodinations are always preferable. In fact, substituting very little I can be misleading, particularly as far as enzymes are concerned. Supposing a sensitive enzyme is inactivated by the substitution of a single iodine atom; if this enzyme is substituted at I/P = 0.01, only one molecule out of 100 will carry a label, and inactivation of this molecule will escape detection because enzyme assays are not sensitive enough to indicate 1% change in activity. (See arginine kinase in Chapter 5, Section I.F.4.a as an example.)
Recent Advances in Diagnosis and Management of Shellfish Allergy
Published in Andreas L. Lopata, Food Allergy, 2017
Sandip D. Kamath, Roni Nugraha, Andreas L. Lopata
Arginine kinase, which was first characterised in the Indian meal- moth, has been identified currently in over seven crustacean and molluscs species according to the IUIS allergen nomenclature, has a molecular weight of 40-42 kDa and is unstable to acid or alkali treatment. Arginine kinase catalysed the transfer of the high-energy phosphoryl group from ATP to arginine, thus yielding ADP and N-phosphoarginine (Yu et al. 2003). IgE sensitisation to arginine kinase has been demonstrated in 21-50% of adults and 67% children (Yang et al. 2010, Kamath et al. 2014). However, the frequency of clinical reactivity to arginine kinase has not been investigated in detail. Crustacean arginine kinase along with TM has been implicated in inhalational exposure and sensitisation among crab processing workers (Abdel Rahman et al. 2011). Similar to tropomyosin, arginine kinase may cause immunological cross-reactivity between crustaceans and molluscs. Although the similarity between octopus arginine kinase and shrimp arginine kinase is less than 54%, their three dimensional structure are highly similar and share identical amino acid sequence in several regions.
Allergen immunotherapy for food allergy from the Asian perspective: key challenges and opportunities
Published in Expert Review of Clinical Immunology, 2019
Agnes Sze Yin Leung, Nicki Yat Hin Leung, Christine Yee Yan Wai, Ting Fan Leung, Gary Wing Kin Wong
Shellfish is an important allergen around the world, and researchers have been actively working on a cure for shellfish allergy. The heat-stable, coiled-coiled secondary structured muscle protein, tropomyosin, has long been identified as the major cross-reactive allergen among edible shellfish (crustaceans and mollusks), and arthropods [73–79]. Tropomyosin has been cloned and well-characterized for its IgE-binding and T cell epitopes [80–86], as well as its thermo-stability [87]. Whilst tropomyosin accounts for 22.5% to 82.8% of IgE sensitization in shrimp-sensitized subjects depending on the geographic location [88,89], other shellfish allergens are also clinically important with sensitization rates ranging from 10% to 50% [90]. These include arginine kinase, myosin light chain, sarcoplasmic calcium-binding protein, troponin C, triose-phosphate isomerase, fatty-acid-binding protein, and hemocyanin [89,91–99].
Arginine-lowering enzymes against cancer: a technocommercial analysis through patent landscape
Published in Expert Opinion on Therapeutic Patents, 2018
Rakhi Dhankhar, Pooja Gulati, Sanjay Kumar, Rajeev Kumar Kapoor
Arginine-catabolizing enzymes include arginine deiminase (ADI), arginase, arginine decarboxylase (ADC), and arginine kinase [8] These can be collectively referred as arginine-lowering enzymes (ALEs). These enzymes differ in their sources: ADI is a prokaryotic enzyme, arginase is the main enzyme of the urea cycle in mammals, ADC has diverse sources including bacteria, plants, and mammals, while arginine kinase is reported in insects, crustaceans, and some unicellular organisms [9]. The anticancerous properties of these enzymes are attributed to various mechanisms like inhibition of protein synthesis, angiogenesis, and induction of apoptotic pathways [10]. Although there are reports supporting the antitumor potential of all these enzymes, ADI is the most preferred enzyme because of its high substrate affinity (Km 0.1–1 mM), high Vmax (50× 103 nmol min−1mg−1), and stability at physiological conditions [11]. Arginase is another highly effective enzyme with broad applicability for both ASS negative and ornithine transcarboxylase-negative tumors [12], but the native enzyme has a short half-life (approximately 30 min), high optimum pH (pH 9.3), low specificity for arginine (high Km 2–4 mM), and low Vmax (34 nmol min−1mg−1) [13]. Various protein engineering techniques like pegylation, attachment to fusion protein, and the replacement of cofactor are currently employed to improve the properties of arginase [14,15]. The enzyme ADC is not preferred in cancer therapy because of its toxic product agmatine [16].
Metal nanoparticles restrict the growth of protozoan parasites
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Oluyomi Stephen Adeyemi, Nthatisi Innocentia Molefe, Oluwakemi Josephine Awakan, Charles Obiora Nwonuma, Omokolade Oluwaseyi Alejolowo, Tomilola Olaolu, Rotdelmwa Filibus Maimako, Keisuke Suganuma, Yongmei Han, Kentaro Kato
The NPs exhibited differential anti-Trypanosoma potential among the three different species of Trypanosoma tested. While AuNP was less effective against T. congolense and T. evansi with an average of ≤50% parasite growth inhibition, AgNP reduced the growth of T. congolense and T. evansi by ≥70%, suggesting that these NPs may have different parasite targets. The finding that AuNP and AgNP showed better efficacy against T. b. brucei may support exploring these NPs as prospective treatment of the human type of trypanosomosis caused by T. b. rhodiense and T. b. gambiense, given that T. b. brucei belongs in the same group and is closer in terms of morphological features to the human Trypanosoma pathogens. Taken together, AuNP and AgNP showed strong anti-Trypanosoma activity, consistent with previously published investigations of the anti-microbial and/or anti-parasite properties of AuNP and AgNP [3,16–19]. Similar studies using PtNP are scarce in the literature except for our recent report [3] that demonstrated the anti-T. gondii property of PtNP. Moreover, our findings herein support our earlier reports that AuNP and AgNP strongly and selectively inhibit recombinant T. b. brucei arginine kinase [23,24]. Arginine kinase is a phosphotransferase that is essential for the growth and survival of T. b. brucei particularly in the bloodstream of the infected host because it helps the parasite meet required energy demands to maintain a reductive environment [23]. Whether the NPs interact with this arginine kinase as a target in suppressing the in vitro growth of Trypanosoma is yet to be determined, but the previous finding [23] indicated that arginine kinase might be a likely parasite target thus this warrants further investigation. Further, because the field of nanomedicine is still emerging, the modes of action of the majority of NPs are yet to be clearly defined. Nevertheless, studies have shown that the generation of reactive oxygen species (ROS) contributes considerably to the anti-parasitic action of NPs including AuNP, AgNP and others [3,36]. However, we cannot yet tell whether ROS production played a part in the action of the NPs against Trypanosoma in the present study. The differential efficacy of the NPs against the different species studied here may be connected to their mode of action, which would suggest that the NPs may affect different parasite targets across the three species of Trypanosoma investigated in this study. Furthermore, the NPs showed ≥200-fold selectivity toward the various species versus the mammalian cell, suggesting that the NPs actually have specificity for Trypanosoma elimination.