Intracellular Peptide Turnover: Properties and Physiological Significance of the Major Peptide Hydrolases of Brain Cytosol
Gerard O’Cuinn in Metabolism of Brain Peptides, 2020
A common feature of many cytosolic peptidases is their dependence on a thiol reducing agent for full activity. This property may be related to the high intracellular content of glutathione which serves to maintain enzyme -SH groups in a reduced state. This feature has led to errors in assignment of a peptidase to a given mechanistic class. For example, prolyl oligopeptidase, a serine proteinase, has features common to both cysteine and serine proteinases (discussed more fully below). It is particularly striking that this enzyme is inactivated by a diazomethylketone inhibitor since such compounds were considered diagnostic of cysteine proteinases14. Thimet oligopeptidase (EC 3.4.24.15) as its name implies has features common to both cysteine and metalloproteinases. It had been considered by some as a cysteine proteinase, however molecular cloning revealed the classic zinc signature of metalloproteinases (discussed below).
Macronutrients
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
The name of an enzyme has two parts. The first part is the name of the substrate, and the second part is terminated with a suffix -ase (54). For example, protease is an enzyme of the substrate protein. For the international nomenclature, the name of an enzyme is preceded by the two letters EC (Enzyme Commission) followed by four numbers. For example, E.C.2.7.1.1. The first number denotes one of the six main classes: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. The second number denotes the subclass and the third number denotes the sub-subclass. The last number denotes the serial number of the enzyme in its sub-subclass (53–54). Enzymes are classified based on the reactions they catalyze into six classes cited above. Oxidoreductases such as glutathione reductase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase are the enzymes that catalyze oxidation-reduction reactions of their substrates. Transferases transfer a functional group between two substrates such as a methyl or phosphate group. Hydrolases catalyze the hydrolysis reactions of carbohydrates, proteins, and esters. Lyases cleave various chemical bonds by other means than hydrolysis and oxidation for the formation of double bonds. Isomerases are involved in isomerization of substrate where interconversion of cis-trans isomers is implicated. Ligases such as alanyl-t-RNA synthetase, glutamine synthetase, and DNA ligases join together two substrates with associated hydrolysis of a nucleoside triphosphate (53–54).
Inflammation
George Feuer, Felix A. de la Iglesia in Molecular Biochemistry of Human Disease, 2020
There is, however, a system of protease inhibitors in tissue fluids which can protect connective tissue macromolecules against the action of proteases released from leukocytes.194,349,456 These antiproteases include α1-M.S.T.-proteinase inhibitor (α1-antitrypsin), α1-antichymotrypsin,348 α2-macroglobulin, and a mucous proteinase inhibitor. The interaction between the endogenous inhibitors of inflammatory cell proteases and the antiproteases is presented in Table 3. The α1-proteinase inhibitor is one of the most important components of the antiprotease system in man, responsible for more than 90% of the inhibitory capacity of normal human serum for regulating neutrophil elastase action.449 The second important inhibitor is the mucous proteinase inhibitor which is not present in the circulation, but is secreted locally by the mucous epithelium of selected organs. This antiprotease inhibits the action of the polymorphonuclear neutrophil-derived elastase. Protease inhibitors in tissue fluids provide a protective role for connective tissue macromolecules against the attack of phagocyte-derived proteases. It is essential that a local balance between inflammatory cell proteases, circulating antiproteases and mucus, exercise control of the degree of tissue damage brought about by the inflammatory process.27
Anticandidal activity of bioinspired ZnO NPs: effect on growth, cell morphology and key virulence attributes of Candida species
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mohammad Jalal, Mohammad Azam Ansari, Syed Ghazanfar Ali, Haris M Khan, Suriya Rehman
Proteinase assay. Proteinase positive C. albicans, C. tropicalis and C. dubliniensis were transferred to 100 ml flasks containing 5 ml YEPD broth (Yeast extract–peptone–dextrose) and incubated at 37 °C for overnight. After incubation, the culture was centrifuged at 3000 rpm, for 5 min and the pellet were washed by phosphate buffer saline (PBS) to remove the residual medium [30]. The suspensions of C. albicans, C. tropicalis and C. dubliniensis were exposed for 1 h at 0.062, 0.125 and 0.25 mg/ml of ZnO NPs. After that, 10 μl suspension of each strain treated or untreated with ZnO NPs were spotted at equidistant points on yeast carbon base (YCB) medium (1.17%) supplemented with 0.2% bovine serum albumin (BSA) and incubated at 37 °C for 3 days. Secreted proteinase enzyme will degrade BSA and form zone of clearance around the yeast colonies. An index (Pz value) was used to represent the extent of proteinase activity by different strains of C. albicans. A Pz value of 1.0 depicts no enzyme activity. It was calculated as follows: The diameter of colony (a) and the diameter of colony (a) plus the diameter of zone of degradation (b).
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.
Porphyromonas gingivalis laboratory strains and clinical isolates exhibit different distribution of cell surface and secreted gingipains
Published in Journal of Oral Microbiology, 2021
Christine A. Seers, A. Sayeed M. Mahmud, N. Laila Huq, Keith J. Cross, Eric C. Reynolds
The involvement of gingipains in the pathogenicity of P. gingivalis has made gingipains promising drug targets for the treatment of P. gingivalis-associated diseases including destructive periodontal disease [30–32]. However, the characteristics of gingipain activities and cell distribution (that is whether the proteinases remain membrane associated or are released into the environment) has not been studied for a range of clinical isolates. Here we have determined the cell-associated and soluble (vesicle-free) gingipain proteinase activities of a panel of global P. gingivalis clinical isolates. We demonstrate widely varied relative proteinase activities between the isolates, particularly in the distribution between cell-associated and soluble forms released into the environment.