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Macronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
An important function of enzymes is in the digestion of foods. The metabolism of protein foods involves a decomposition into single amino acids by different digestive enzymes (amylase, protease, pepsin, trypsin, and chymotrypsin) from the stomach to the small intestine. Before the absorption in the small intestine, most proteins must be reduced to single amino acid or peptides by specific protein enzymes. Most peptides longer than four amino acids are not absorbed and must be broken into single amino acids. Enzyme production and activity can be decreased with age and illness. Enzymes are present in all foods. However, heat used in cooking, drying, or processing can destroy them. Therefore, fresh foods like fruits and some vegetables are rich in enzymes and help digestion. Some people like to eat raw meat such as raw beefsteak and raw fresh fish; this habit might be helpful for digestion. Enzymes extracted from fruits like papaya, pineapple, kiwifruit, and fig are used as medicines, food-processing agents and dietary supplements. Fruits like papaya, kiwifruit, pineapple and figs are rich in proteases such as papain, actinidin, bromelain, and ficin, respectively, which aid the breakdown of proteins.
Inherited Differences in Alpha1-Antitrypsin
Published in Stephen D. Litwin, Genetic Determinants of Pulmonary Disease, 2020
The physiologic importance of proteinase inhibitors can best be demonstrated by experiments of nature in which there is a genetically determined absence or very low concentration of a specific inhibitor. Thus, an inherited low concentration of antithrombin III is associated with intravascular thrombosis presumably due to excessive thrombin activity [2], a genetically determined deficiency of a complement esterase inhibitor in serum leads to hereditary angioneurotic edema [3], and alpha1-antitrypsin deficiency is associated with pulmonary emphysema, as is discussed in detail later.
Proteinase Inhibitors: An Overview of their Structure and Possible Function in the Acute Phase
Published in Andrzej Mackiewicz, Irving Kushner, Heinz Baumann, Acute Phase Proteins, 2020
Proteinase — Many authors use the terms protease and proteinase interchangeably, but they do have separate definitions. Proteolytic enzymes are divided into exopeptidases and endopeptidases, depending upon where in a peptide or protein chain they cut. The term proteinase is synonymous with endopeptidases, whereas the term protease refers to both exo- and endopeptidases. Recent nomenclature revisions by the International Union of Biochemistry recommend replacing protease by peptidase and proteinase by endopeptidase, but we stay with the established terms in this chapter.
Different chemical proteomic approaches to identify the targets of lapatinib
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Tatjana Kovačević, Krunoslav Nujić, Mario Cindrić, Snježana Dragojević, Adrijana Vinter, Amela Hozić, Milan Mesić
Chemical proteomic approaches for identification of the protein targets of bioactive small molecules have been reviewed elsewhere.2–6 The main advantage of the chemical proteomics approach is the isolation and identification of proteins targets from the cellular environment, in which protein conformations, post-translational modifications and protein complexes are preserved. The bioactive small molecules were derivatized by introducing a reactive group via various linkers, followed by their immobilisation onto a solid support. Primary amines, alkynes and photoreactive group7–9 are groups that are frequently used for derivatization of bioactive molecules, using linkers of various structures and lengths. Solid supports also vary, with sepharose- and agarose-based polymers (resins) being the matrices used most often. Typically, protein mixtures, obtained from cell lysates or tissue homogenates, are incubated with immobilised ligands on these resins. Proteins that interact with the ligand-matrix can then be subjected to either an in-solution sequence-specific protease digestion or separated by electrophoresis, followed by in-gel sequence-specific protease digestion. The digests are then submitted for mass spectrometry analysis, to support identification of potential targets and off-targets. These proteins can then be validated through specific biochemical or cellular assays.
Pharmaceutical, biomedical and ophthalmic applications of biodegradable polymers (BDPs): literature and patent review
Published in Pharmaceutical Development and Technology, 2022
Barzan Osi, Mouhamad Khoder, Ali A. Al-Kinani, Raid G. Alany
Biodegradable polymers (BDPs) are simply, a class of polymeric materials that possess the ability to decompose into small units, without causing harm to the body (Tamariz and Rios-Ramrez 2013). The biodegradation process occurs through the breakdown of the polymeric chains by either enzymatic or nonenzymatic mechanisms. In enzymatic degradation, the process is carried out by special enzymes (Lin and Anseth 2013). Natural polymers are usually more susceptible to enzymatic degradation. However, synthetic polymers can undergo enzymatic degradation. For instance, proteinase K and lipases enzymes biodegrade poly(l-lactide) and poly(ε-caprolactone) respectively (Niemelä and Kellomäki 2011). In the case of nonenzymatic degradation, the backbone of the polymer cleaves in the presence of water, where water molecules permeate the bulk of the polymer and randomly break down the chemical bonds, leading to a reduction in the polymer molecular (Lin and Anseth 2013). In contrast to BDPs, non-BDPs consist of long hydrocarbon chains involving chemical bonds that cannot be broken down by biological processes (Imazato et al. 2017). An obvious advantage of using BDPs is that no surgical removal is needed after the clinical application. Indeed, BDPs can safely be metabolised and eliminated from the human body through normal metabolic pathways which is not the case of non‐BDPs that could potentially accumulate in different body tissues where they may induce toxicity.
Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Xianyin Lai, Jason Tang, Mohamed E.H. ElSayed
To overcome the proteolytic degradation, strategies have been taken based on the administration of the peptide, protein, and antibody drugs. For oral delivery, various approaches have been applied to address the proteolytic stability challenge. Formulation approaches such as liposomes provide a technique to physically separate the drugs from enzymes to avoid proteolytic degradation [18]. Altering the local pH at the delivery site by formulation is able to inhibit the resident peptidases since the optimal pH for the enzymes is changed [21]. Directly using proteinase inhibitors to co-formulate with peptides provides localized protection of peptides [22]. To avoid complex formulations and safety concerns about enzyme inhibition, changing amino acids around the cleavage sites provides a solution for increasing peptide intrinsic proteolytic stability to avoid degradation [23]. For subcutaneous, intravenous, and other non-oral drug delivery approaches, modifying the liable amino acids is the only way to improve their proteolytic stability.