China
Africa
Explore chapters and articles related to this topic
Biochemical Effects in Animals
Published in Stephen P. Coburn, The Chemistry and Metabolism of 4′-Deoxypyridoxine, 2018
Mekhanik et al.308,309 found that after simultaneous incubation of glutamate decarboxylase from Escherichia coli with 5 × 10−6 Mpyridoxal phosphate and 3.3 × 10−4 M analog, pyridoxine phosphate produced 76% inhibition (K, 2 × 10−5 M), 4′-deoxypyridoxine phosphate 46% (no K, value), 5′-deoxypyridoxal 19% (K, 4 × 10−4), 3-deoxypyr-idoxal phosphate 35% (K, 1 × 10−4), and pyridoxamine phosphate 10% (K, 2 × l(r3). Based on data from these and other analogs, the authors concluded that glutamate decarboxylase is more susceptible to alterations in cofactor structure than arginine decarboxylase or aspartate aminotransferase. They also noted that while the 2-methyl and 5′-phosphate groups are not essential for nonenzymic decarboxylation, they are essential for proper interaction with enzymes. 3-Deoxypyridoxal failed to form in aldimine bond with the enzyme as evidenced by the failure of treatment with sodium borohydride to permanently inactivate the enzyme.
Affinity Modification in Biochemistry, Biology, and Applied Sciences
Published in Dmitri G. Knorre, Valentin V. Vlassov, Affinity Modification of Biopolymers, 1989
Dmitri G. Knorre, Valentin V. Vlassov
Since putrescine and spermidine are absolute requirements for the growth of some bacteria and fungi, attempts have been made to develop approaches to control bacterial growth by specific interference with the polyamine biosynthesis. Since most bacteria can synthesize polyamines from several precursors, several enzymes should be inhibited to achieve efficient polyamine deprivation. It was demonstrated that growth of bacteria E. coli and P. aeruginosa can be markedly slowed by a combination of d,l-α-monofluoromethylornithine (suicide inhibitor of ornithine decarboxylase), d,l-α-difluoromethylarginine (suicide inhibitor of arginine decarboxylase), and dicyclohexylammonium sulfate (competitive inhibitor of spermidine synthase). The results obtained suggest that the approach based on the inhibition of polyamine biosynthesis may be a viable approach toward the control of certain bacterial infections.550
Alternative Tumor-Targeting Strategies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Arginase is an enzyme produced in the liver and other mammalian tissues and is responsible for the fifth and final step in the urea cycle which involves the conversion of L-arginine into L-ornithine and urea (Figure 10.15). Two isoforms of the enzyme (i.e., isozymes) are known to exist, one (Arginase I) that is involved in the urea cycle and is located primarily in the cytoplasm of the liver, and the other (Arginase II) that regulates arginine/ornithine concentrations in cells. In other species, arginine can also be degraded by arginine decarboxylase and arginine deiminase (ADI), neither of which is expressed in mammalian cells. In human tissues and organs, arginine is obtained via protein degradation and dietary intake, and healthy cells can also synthesize arginine intracellularly from ornithine via citrulline mediated by the enzymes ornithine carbamoyl transferase (OCT), argininosuccinate synthetase (ASS), and argininosuccinate lyase (ASL). However, OCT expression in both tumor and healthy cells is usually down-regulated when supplies of arginine are adequate. Catabolism of the amino acid L-Arginine to L-Ornithine and urea by the enzyme arginase.
The interplay between aryl hydrocarbon receptor, H. pylori, tryptophan, and arginine in the pathogenesis of gastric cancer
Published in International Reviews of Immunology, 2022
Marzieh Pirzadeh, Nastaran Khalili, Nima Rezaei
Malignant tumors are featured with high metabolic activity, and to meet their drastic growth, they expand nutritional needs [120]. Some tumors named as arginine auxotrophic are not able to synthetize arginine independently. In these tumors, arginine depletion has been described to be a potential anti-tumor treatment [121,122]. It has been investigated that some malignant tumors have high levels of arginase, which converts arginine to urea and ornithine and subsequently causes a reduction in arginine level in tumor margins, leading to immunosuppression [123]. Arginine has a direct effect on tumor growth. Some tumor cells need arginine for their growth; thus, arginine metabolizing enzymes such as arginine deiminase, arginine decarboxylase, and arginase which cause arginine depletion in the tumor microenvironment could be potentially used for arginine deprivation therapy [124–126]. Arginine succinate synthetase 1 (ASS1) is a rate-limiting enzyme in arginine biosynthesis [127]. In gastric cancer cell lines, ASS1 expression is increased. In a recent study, silencing ASS1 through the use of vector-mediated short hairpin RNA expression seemed to notably decrease tumor metastasis and cell migration. Similarly, arginine depletion in gastric cancer cell lines reduced cell migration remarkably [128].
Intestinal luminal putrescine is produced by collective biosynthetic pathways of the commensal microbiome
Published in Gut Microbes, 2019
Atsuo Nakamura, Takushi Ooga, Mitsuharu Matsumoto
We investigated whether bacteria harbouring enzymes that synthesise polyamines from arginine are present in faeces, based on 16S rRNA gene sequencing data. On average, 35,115 usable sequence reads were obtained per faecal sample by using Ion PGM, a system for next-generation sequencing. The 2,400 OTUs detected in all samples were identified by RDP classifier as belonging to 48 genera (Table S3). All sequence data were deposited in the DDBJ sequence read archive database under accession number (DRA006802). Predictive functional gene profiling was performed by 16S rRNA gene sequencing using Piphillin, which utilizes 16S rRNA taxonomic information to predict functional attributes of microbial assemblages.30 Analysis using Piphillin suggested the presence of multiple polyamine synthesis genes, including arginine deiminase (ADI), ornithine carbamoyltransferase (OTC), ornithine decarboxylase (ODC), arginine decarboxylase (ADC), agmatine ureohydrolase (AUH), agmatine deiminase (AgDI), putrescine carbamoyltransferase (PCT), N-carbamoyl putrescine amidase (NCP), S-adenosylmethionine carboxy-lyase (AdoMetDC), spermidine synthase (SPDS), and carboxyspermidine decarboxylase (CASDC), in the microbial communities (Table 2). The results suggested that the microbiota in the rat intestine harbours enzymes that synthesise putrescine and spermidine from arginine.
Population pharmacokinetics of arginine glutamate in healthy Chinese volunteers
Published in Xenobiotica, 2018
Jing Wang, Heng Zheng, Kun Wang, Zheng Wang, Yufeng Ding
Arginine can produce ornithine by arginase in the liver. Ornithine participates in the urea cycle and promotes the generation of the urea (Grillo & Colombatto, 2004), decreasing the blood ammonia level. Contrary to that of glutamate, the ammonia detoxification effect of arginine is slow but lasts longer (Harper & Najarian, 1956a). The metabolism of arginine is mainly related with arginase, nitric oxide(NO) synthases, arginine:glycine amidinotransferase and arginine decarboxylase (Morris, 2016). NO produced by arginine/NO pathway (Moncada et al., 1991) plays a key transmitter role in the relaxation of blood vessels, anti-platelet aggregation and neuron activity. NO is also involved in microbicidal effect, anti-tumor effect, immune processes and sperm physiology. Therefore, arginine has multiple effects in cardiovascular system (Anderson et al., 1995), immune system (Qiao et al., 2005), digestive system (Lazaratos et al., 1995), CNS (Burnett et al., 1995) and reproductive system (Greene et al., 2012; Liu et al., 2012; Salvolini et al., 2012) and has good curative effects on several diseases.