Selective Drug Delivery Using Targeted Enzymes For Prodrug Activation
Siegfried Matzku, Rolf A. Stahel in Antibodies in Diagnosis and Therapy, 2019
Since these studies, many applications of targeted oxidase enzymes have been reported (Ito et al., 1989). Glucose oxidase and lactoperoxidase were linked to a pan-leukocyte specific mAb and it was shown that the conjugates in combination with glucose and iodide led to cytotoxic activities on T-cells (Ito et al., 1990). Immunologically specific cytotoxic activities have also been obtained with conjugates of xanthine oxidase in combination with xanthine or hypoxanthine (Battelli et al., 1988; Dinota et al., 1990). Evidence that the activities were due to the formation of reactive oxygen species was based on the abilities of catalase and superoxide dismutase to neutralize the cytotoxic effects. Consistent results were obtained in recently reported in vivo studies using a subcutaneous tumor model in rabbits (Yoshikawa et al., 1995). It was found that antitumor activity could be obtained by localized administration of xanthine oxidase followed by systemic hypoxanthine treatment.
Growth Regulating Substances in Mosses
R. N. Chopra, Satish C. Bhatla in Bryophyte Development: Physiology and Biochemistry, 2019
In vivo about 35 to 40% of the initial activity of kinetin could be detected in adenine and about 5 to 10% in hypoxanthine. It appears that in addition to cytokinin oxidase a deaminase must be present in the extract. In vivo labeled products have been identified, as shown in Figure 5. If [3H]-isopentenyladenosine is used for labeling in vitro, much less adenine is found, but about 30% isopentenyladenine, 15% inosine, and 10% hypoxanthine could be detected (Figure 6). A constant but low level of 2iP always remains in the cells, which is in agreement with the physiological experiments using 2iP treatment. The enzyme cytokinin oxidase extracted from the moss tissue is not completely identical to the enzyme from higher plants because 2iP is the better substrate for the latter whereas kinetin is better for the enzyme from the moss tissue.43,53
Free radicals in biology
Roger L. McMullen in Antioxidants and the Skin, 2018
In general, enzymes can be sources of free radicals as they are often involved in electron transfer reactions, which occasionally result in the leakage of electrons.2 In addition, various enzymes that serve roles as oxidases can potentially be sources of free radical species. Several examples include: D-amino acid oxidase: This enzyme is responsible for the eradication of unwanted amino acids in the cell.Xanthine oxidase: As part of purine metabolism, the degradation of hypoxanthine to xanthine and xanthine to uric acid is achieved by xanthine oxidase (Chapter 3).Nitric oxide synthase: Actually, this is a family of enzymes that is responsible for the synthesis of NO•.Myeloperoxidase: During phagocytosis (already discussed) this enzyme is responsible for the formation of HOCl.NADPH oxidase: As a membrane-bound protein, this enzyme participates in the production of O2•− during phagocytosis.
Molecular structure investigation towards pharmacodynamic activity and QSAR analysis on hypoxanthine using experimental and computational tools
Published in Egyptian Journal of Basic and Applied Sciences, 2018
G. Susithra, S. Ramalingam, S. Periandy, R. Aarthi
The Hypoxanthine is normally belongs to heterocycles family which peculiarly contains pyrimidine and imidazole rings. Hypoxanthine is a purine derivative with nitrogenous base rarely found as a constituent nucleic acid [1]. Heterocycles showing in their strange structures where the pyrimidine ring is fused to azolic moieties, are interesting systems being with important biochemical, pharmacological and physicochemical property [2,3] . During the recent decades numerous pyrimidine derivatives have found to have wide clinical and pharmacological applications [4]. Particularly, fused pyrimidine with Imidazole ring persists to attract considerable attention since their great practical usefulness, primarily due to very wide spectrum of biological activities [5,6] . The hypoxanthine naturally has different Tautomerism which resolves the specific prototype of hydrogen bond donors and acceptors present in a specific molecule. Similarly, the fused imidazole and its derivatives are generally having bioactivity against inflammatory mediators [7].
Mass spectrometry-based untargeted metabolomics study of non-obese individuals with non-alcoholic fatty liver disease
Published in Scandinavian Journal of Gastroenterology, 2023
Metin Demirel, Fatmanur Köktaşoğlu, Esin Özkan, Halime Dulun Ağaç, Ayşe Zehra Gül, Rasul Sharifov, Ufuk Sarıkaya, Metin Başaranoğlu, Şahabettin Selek
Toledo-Ibelles et al. aimed to investigate the in-vivo relationship between NAFLD and hyperuricemia in rabbits fed a high-fat diet. They detected impaired purine metabolism due to increased hypoxanthine metabolite levels. Moreover, they demonstrated that the hypoxanthine increase was associated with increased oxidative stress in hepatocytes [25]. In addition, Ge et al. reported a decrease in fecal xanthine levels in individuals with NAFLD. In the present study, an increase in hypoxanthine metabolite was also detected. The increase in hypoxanthine metabolite in non-obese NAFLD patients suggests that this metabolite increases independent of diet.
Metabolomic evaluation of Euphorbia pekinensis induced nephrotoxicity in rats
Published in Pharmaceutical Biology, 2018
Zhenzhen Liu, Yan Zeng, Pengyi Hou
The kidney metabolite profile results indicated that the hypoxanthine level was significantly decreased in the PE-treated rats compared with the HCG rats. Hypoxanthine is a spontaneous deamination product of adenine, and the relationship between hypoxanthine and renal damage is due to the proteolytic conversion of xanthine dehydrogenase to xanthine oxidase (Zhao et al. 2013). What is more, the end product of hypoxanthine catabolism is uric acid which could deposit in renal tissue and form renal calculi. As hypoxanthine was decreased in this study, uric acid was likely to accumulate in kidney and produce renal damage.
Related Knowledge Centers
- DNA
- Inosine
- Nucleic Acid
- Organic Compound
- Plasmodium Falciparum
- Purine
- Reagent
- Rna
- Transfer Rna
- Transfer Rna
- Malaria Culture
- DNA
- Rna