Amounts Of Flavin Mononucleotide Research Articles

A metabolomics strategy to explore urinary biomarkers and metabolic pathways for assessment of interaction between Danhong injection and low-dose aspirin during their synergistic treatment.

The drug combination of Danhong injection (DHI) and low-dose aspirin (ASA) was frequently applied for the treatment of cardiovascular and cerebrovascular diseases. Due to the drug interactions, a lot of potential benefits and risks might exist side by side in the course of combination therapy. However, there had been no studies of interaction between DHI and ASA. Metabolomics was a powerful tool to explore endogenous biomarkers and metabolic pathways. In present study, metabolic profiling with ultra-high-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF/MS) coupled with multivariate statistical analysis was performed to provide insight into understanding the interaction between DHI and low-dose ASA. Eleven potential biomarkers of three types were identified and seven metabolic pathways were constructed. The results showed that the interaction between DHI and low-dose ASA during synergistic treatment indeed affected some key endogenous biomarkers and metabolic pathways, which could not happen when DHI or low-dose ASA was used alone. The quality and quantity of endogenous metabolite were both influenced by interaction between DHI and low-dose ASA. In details, the amount of flavin mononucleotide, L-2, 4-diaminobutyric acid (DABA) and 4-aminohippuric acid were significantly increased. On the contrary, the amount of 3-methyluridine, 4, 6-dihydroxyquinoline, cortolone-3-glucuronide, and serotonin were significantly decreased. Furthermore, O-phosphotyrosine, 3-methyl-2-butenal, indoxyl sulfate and dolichyl diphosphate were disappeared in urine. As to metabolic pathways, riboflavin metabolism, pentose and glucuronate interconversions, and tryptophan metabolism were all significantly influenced. The emerging alterations of biomarkers and metabolic pathways were associated with a lot of drugs and diseases based on literature researches, which might influence the co-administration of other drugs or the treatments of relevant diseases. Our paper presented some hints to uncover the mechanism of interaction between DHI and low-dose ASA, which would provide some references for application of DHI and low-dose ASA combination.

Identification and characterization of an archaeon-specific riboflavin kinase.

The riboflavin kinase in Methanocaldococcus jannaschii has been identified as the product of the MJ0056 gene. Recombinant expression of the MJ0056 gene in Escherichia coli led to a large increase in the amount of flavin mononucleotide (FMN) in the E. coli cell extract. The unexpected features of the purified recombinant enzyme were its use of CTP as the phosphoryl donor and the absence of a requirement for added metal ion to catalyze the formation of FMN. Identification of this riboflavin kinase fills another gap in the archaeal flavin biosynthetic pathway. Some divalent metals were found to be potent inhibitors of the reaction. The enzyme represents a unique CTP-dependent family of kinases.

Regulatory Mechanisms of 6,7-Dimethyl-8-Ribityllumazine Formation in Resting Cells of a Riboflavin-Adenine-Deficient Mutant of Bacillus subtilis

The regulatory mechanisms of riboflavin biosynthesis in the resting cells of a riboflavin-adenine-deficient mutant of Bacillus subtilis were examined. The growth and pH of the medium remained unchanged in spite of the administration of 0-200 microg/mL riboflavin to the medium during incubation of the resting cells for 17 h. However, the formation of 6,7-dimethyl-8-ribityllumazine (DMRL) and flavin adenine dinucleotide (FAD) was restricted and augmented and then reached its plateau, showing an inverse relation in the addition of riboflavin up to 50 microg/mL to the medium and a parallel relation in the supplementation of riboflavin up to 200 microg/mL to the medium. In the experiments, the amount of flavin mononucleotide (FMN) was negligible and riboflavin was not detected in the resting cells. The results indicated that not the repression of related enzymes but negative feedback inhibition by FAD, but not that by riboflavin or FMN, is operative in the biosynthetic pathway of riboflavin in the riboflavin adenine double-less mutant of Bacillus subtilis.

Studies on the Mechanism of Riboflavin Sparing Action by D-Sorbitol in Rat (Report 2)

It was previously confirmed that D-Sorbitol has the riboflavin sparing action in rats. When sorbitol is supplemented in the diet of rats, the almost vitamin synthesis in the intestine of rats occur in cecum.So, it is most important problem to investigate that the vitamin synthesized in cecum exist in what form to confirm the mechanism of vitamin sparing action.Then, in this paper the following experiments have been performed. The diet composition was shown in Table 1. The content of cecum of rats in 15% sorbitol diet group after one month feeding was gently homogenated with mortar. The supernatant and precipitate were obtained by twice centrifuging the homogenate for 30 minutes at 11, 000r.p.m.The combined precipitate was dilluted with water and was treated 80°C, 15 minutes, and after was centrifuged for 20 minutes at 3, 000 r.p.m.The riboflavin content and the three different type of riboflavin in supernatant and precipipate were measured by Yagi's riboflavin assay method, respectively.The results are shown in Table 2-3 and Figure 1.The riboflavin content in supernatant and precipitate are approximately 10μg and 110μg in average, respectively. Only flavin mononucleotide (FMN) was found in supernatant solution, but in precipitate the great amounts of flavin adenine-dinucleotide and flavin mononucleotide and a trace amount of free riboflavin (FR) were found.It is very interesting to be finding only (FMN) in supernatant. It is the important problem to research by what and from what FMN is occurred, or whether FMN in supernatant is directly absorbed from cecum or not.At any rate, the following experiment has been done. The supernatant solution was dialyzed with distilled water by using cellophan tube for 2 day at 0-2°C. The result in table 3 showed that the considerable amounts of FMN was dialyzed. This result seems to indicate that FMN transfered to supernatant in cecum may be absorbed from cecum.

The nature of compounds present in mixtures of oxidized and reduced flavin mononucleotides

Abstract : The composition of the equilibrium mixtures obtained on mixing known amounts of flavin mononucleotide (FMN) and reduced FMN (FMNH2) were studied by spectrophotometry, fluorimetry, and E.S.R. spectrometry. The major component of the mixtures containing more than 2mM total flavin is a species absorbing at 900 millimicrons which we regard as a charge transfer complex between FMNH2 and FMN. Comparison of the spectrophotometric and E.S.R. data show a close correlation between the extinction at 570 millimicron and the concentration of free radical. When the radical concentration is plotted against total percentage of reduced flavin at constant flavin concentration, a strongly asymmetric curve is obtained, peaking at about 70% reduction. Evidence is presented that this asymmetry is due to the presence of another radical species, a complex between the semiquinone and FMNH2. The formation of the complex between semiquinone and FMNH2 is inhibited in the presence of solutes such as caffeine and urea and in various organic solvents. (Author)