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Preformulation of New Biological Entities
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Riccardo Torosantucci, Vasco Filipe, Jonathan Kingsbury, Atul Saluja, Yatin Gokarn
Light can also promote the oxidation of proteins through two different photo-processes [73]. Photooxidation of tryptophan, tyrosine, and cysteine can yield several products, including N-formylkynurenine, oxoindole, dityrosine, as well as sulfonic and sulfinic acid [74]. Light-induced degradation of the disulfide bonds can furthermore lead to a series of photoproducts such as thioethers and dithiohemiacetals [75]. The latter was found also in crystalline and amorphous insulin and was responsible for the generation of new cross-links [76]. Similarly, UV light was responsible for covalent insulin dityrosine dimerization and disulfide bond photolysis [77]. Light can promote sequence-specific formation of D-amino acids in mAb solutions [78], which may result in a color change or precipitate formation. Importantly, the effect may not be visually detectable and can modify excipients that can further be involved or lead to additional degradation products. Strategies to prevent oxidation include the use of chelating agents [79,80], radical scavenger excipients, or via site-specific mutagenesis to substitute the susceptible amino acid(s) [60].
Biological Strategies in Nanobiocatalyst Assembly
Published in Grunwald Peter, Biocatalysis and Nanotechnology, 2017
Ian Dominic F. Tabañag, Shen-Long Tsai
Another approach in the utilization of dityrosine cross-linking in the synthesis of cross-linked enzyme aggregates (CLEA is by enzyme mediated oxidative cross-linking as discussed above. Minamihata et al. (2011b) first demonstrated the use of the site-specific peroxidases-mediated cross-linking of a Y-tagged (GGGGY) alkaline phosphatase (AP). They utilized the enzyme horseradish peroxidase (HRP) to catalyze the dityrosine crosslinking between the tyrosine residues of the Y-tagged AP and reported that the relative enzyme activity of the cross-linked AP was 95% when compared to the free AP (wild type). In a subsequent study by the said research group (Minamihata et al., 2011a), they demonstrated the immobilization of AP onto biotin-coated plates by cross-linking the Y-tagged AP with a Y-tagged streptavidin (SA) via HRP-mediated dityrosine crosslinking. It was also reported that the AP-SA conjugate (using the GGGGY as the Y-tag) immobilized on the biotin-coated plate (the mode of immobilization in this case is not a covalent type but via the streptavidin-biotin affinity binding) exhibited a high enzymatic activity because of the higher heteroconjugation efficiency.
Recombinant Resilin—A Protein-Based Elastomer
Published in Anil K. Bhowmick, Current Topics in ELASTOMERS RESEARCH, 2008
Mickey G. Huson, Christopher M. Elvin
The extent of dityrosine formation increased with time of irradiation to a maximum near 20% (relative to total tyrosine) after 30 s (Figure 9.19a). Samples with >17% dityrosine were solid, while those with lesser degrees of cross-linking were not. By comparison, Andersen [33] showed that about 25% of tyrosine occurs as the dityrosine dimer in natural locust wing hinge resilin. The deduced amino acid sequence of recombinant resilin (molecular weight 28,492 Da) contains 17 tyrosine residues; thus, from these data, the molecular mass between cross-links (Mc) can be estimated as 8500 Da. This assumes that all dityrosine molecules form effective cross-links; however, many may be intramolecular leading to a higher actual Mc. The effect of increased cross-linking on physical properties is shown in Figure 9.19b and c. The penetration of an SPM tip into the sample is inversely proportional to the modulus and shows the material getting stiffer with increased exposure time. The resilience increases to a plateau initially but decreases at long exposure times, suggesting some change to the network, even though this is not reflected in the dityrosine level or modulus.
Storage stability of powdered dairy ingredients: a review
Published in Drying Technology, 2021
Arissara Phosanam, Jayani Chandrapala, Bogdan Zisu, Benu Adhikari
Scheidegger et al.[108] evaluated oxidative modifications of proteins in milk powders. In this study, WMP, SMP, and infant formula powders (IFP) were stored at 24 °C or −20 °C for 9 months restricting their exposure to light. Protein oxidative status was measured as protein carbonyl content, dityrosine content, and extent of protein polymerization. The level of protein carbonyl was slightly lower in SMP than in WMP, whereas IFP had more than twice as much protein carbonyl as WMP. No differences were detected in dityrosine content. The authors found that protein carbonyl level, whey protein content, and the level of protein aggregation had a correlation among them. The protein carbonyl content increased in all tested samples after 9 months of storage at both temperatures. The findings suggested that a better understanding of protein oxidation could help devising storage parameters that could extend the shelf life of protein-rich dairy ingredients.[108]
Young and mature leaves of Azadirachta indica (neem) display different antidiabetic and antioxidative effects
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Abubakar Mohammed, Raushan Kumar, Fauzia Ashfaq, Abdulrahman A. Alsayegh, Azza Abd El Hafiz Al Areefy, Mohammad Idreesh Khan, Syed Ibrahim Rizvi
Advanced oxidation protein products (AOPP) are an established method for measuring short-term changes in oxidative stress because it rapidly responds to changes [21]; they are the products formed when there is the oxidation-modification of albumin, fibrinogen, and lipoproteins and oxidative stress is said to be greatly involved in this process [22]). When amino acid residues such as tyrosine undergo oxidation, it leads to the formation of dityrosine, aggregation of the protein, crosslinking, and fragmentation occur when ROS-mediated protein damage takes place in vitro [16]. The plasma levels of AOPP are elevated in patients with diabetes mellitus and other diseases that involve oxidative stress [23,24].
Anticlastogenic and hepatoprotective effects of Kolaviron on sodium valproate-induced oxidative toxicity in Wistar rats
Published in Egyptian Journal of Basic and Applied Sciences, 2021
Olaniyi Solomon Ola, Kayode Ezekiel Adewole
AOPPs which were first detected in chronic uremic patients are dityrosine-containing cross-linked protein products with utility in the evaluation of the degree of oxidant-mediated protein damage [25,43]. AOPPs are a precocious marker of oxidized proteins and circulate for prolonged periods in the blood as cells only degrade them within hours and days. AOPPs when determined in the liver can be considered as a marker for monitoring oxidative stress in drug-induced hepatotoxicity [44]. The generation of intracellular oxidized proteins is associated with increased production of ROS which results from a disruption in the balance between pro-oxidants and antioxidants [45]. It is produced in plasma when the plasma albumin is subjected to oxidation by various oxidants like ROS and hypochlorous acid [46], and its elevated levels have been associated with some pathological conditions, such as atherosclerosis, diabetes, nephropathies and cancer [47]. Sulfhydryl (SH) group has been shown to be sensitive to oxidative damage and its depletion was associated with certain pathological condition-like ischemia insult [48]. The thiol content especially sulfhydryl groups on albumin protein are considered as main antioxidants in plasma or reducing groups in the body fluids. It has been shown that reduced levels of protein thiols correlates negatively with the levels of AOPPs [49]. The significant increase in the level of plasma AOPPs with concomitant reduction in plasma total thiol observed in VPA-treated animal group relative to control in this study suggests the induction of oxidative stress as a result of SVP treatment with subsequent damage to tissue proteins. However, coadministration of biflavonoid Kolaviron significantly reduced the elevated level of AOPPs in drug-treated group and effectively restored the total thiol status when compared to SVP alone treated group. This shows that Kolaviron may improve plasma antioxidant activity by preserving surfydryl protein pools.