Description
Phenazine is a free radical generator. It has been used as an electron transfer reactant in cell viability assays. Phenazine (10 μM) induces ssDNA break formation in the presence of the reducing agent NADPH in a cell-free plasmid cleavage assay when used at a concentration of 10 μM. It induces oxidative DNA damage in an alkaline comet assay and apoptosis in A375 melanoma cells when used at a concentration of 10 μM. Phenazine (20 nM) oxidizes cysteine-containing proteins in HepG2 cells.
Chemical Properties
orange to light brown crystals or powder
Uses
Phenazine Methosulfate is used in tyrosine transaminase test and for enzymic determination of ethanol in blood by the colorimetric micromethod. Used with ascorbic acid to determine nitric oxide reductase activity. Since the reduced PMS is easily oxidized by oxygen, it is used in assays as an electron carrier between enzymes and oxygen, cytochrome c, indophenols, or tetrazolium salts. The reduced PMS is used as an electron donor to reduce cytochrome c or in photosynthetic experiments. Usage of PMS for detection of specific dehydrogenases has been reported.
Definition
ChEBI: 5-methylphenazinium methyl sulfate is an azaheterocycle sulfate salt and a member of phenazines. It is used as an electron carrier in place of the flavine enzyme of Warburg in the hexosemonophosphate system and also in the preparation of succinic dehydrogenase. Green et al., J. Biol. Chem. 217, 551 (1955).
Application
Phenazine methosulfate is a compound used to determine nitric oxide reductase activity. Phenazine methosulfate has been used:
as a component of succinate dehydrogenase enzyme substrate solution.
to induce superoxide radical generation in red blood cell suspensions and to study its influence on RBC deformability.
as a component of complex II histochemistry media.
Used in the discovery of potent bromophenazine antibacterial agents against Staphylococcus.
General Description
Phenazines are heterocyclic compounds produced as secondary metabolites by bacteria.
Biochem/physiol Actions
Phenazine methosulfate (PMS) acts as a good electron acceptor. PMS is reduced non-enzymatically by (nicotinamide adenine dinucleotide) NADH and (nicotinamide adenine dinucleotide phosphate) NADPH.
Enzyme inhibitor
This redox-active reagent (FW = 306.34 g/mol; CAS 299-11-6; Eo’ = +0.080 V, pH = 7 and T = 30°C), also known as N-methylphenazoniummethosulfat, is frequently used as an artificial electron acceptor and carrier in studies of redox reactions. The reduced semiquinone, which may be prepared nonenzymatically from NADH or NADPH, is a colorless product (occasionally, a green color is reported) and can be used as an electron donor. This reduced compound is rapidly oxidized by dioxygen and will reduce cytochrome c, indophenol dyes, and many other electron acceptors. It is often used with ascorbic acid to determine nitric oxide reductase activity. Action as a Redox Substrate: Phenazine methosulfate (MTT) is a synthetic electron acceptor substtrate for many enzymes (e.g., succinate dehydrogenase, holine dehydrogenase, glycolate dehydrogenase, polyvinylalcohol dehydrogenase, (R)-pantolactone dehydrogenase, formate dihydrogenase, isoquinoline 1-oxidoreductase, quinaldate 4-oxidoreductase, aralkylamine dehydrogenase, glycine dehydrogenase (cyanide-forming), trimethylamine dehydrogenase, cytokinin dehydrogenase, and 4-cresol dehydrogenase (hydroxylating). When used in enzyme assays, MTT is converted to formazin, an intensely purple-colored product. To achieve high-sensitivity and a linear dependence, one must use a solubilization solution (usually either dimethyl sulfoxide, an acidified ethanol solution, or a solution of the detergent sodium dodecyl sulfate in diluted hydrochloric acid) to disperse/dissolve the otherwise insoluble formazan to obtain colored suspension/solution. The absorbance of this solution may then be quantified by measuring the wavelength between 500 and 600 nm in a spectrophotometer. The degree of light absorption depends on the solvent. Cell Viability Asaays: MTT has been widely employed in colorimetric assays for assessing the viability of cells. When tested under defined conditions, NAD(P)H-dependent cellular oxidoreductase enzymes catalyze the conversion of MTT to formazan, the intensity of which indicates cell viability. Other related tetrazolium dyes (including XTT, MTS and the WSTs) are used in conjunction with the intermediate electron acceptor, 1- methoxy phenazine methosulfate (PMS). Target(s): ferredoxin:NADPcyclase; photophosphorylation; progesterone monooxygenase; protein-Np -phosphohistidine:sugar phosphotransferase; stearoyl-CoA 9- desaturase; steroid 9a-monooxygenase; steroid 11bmonooxygenase; and testosterone 5a-reductase.
Purification Methods
It forms yellow-brown prisms from EtOH (charcoal), or EtOH/Et2O. Its solubility in H2O at 20o is 10%. In the presence of aqueous KI it forms a semiquinone which crystallises as blue leaflets from EtOH. [Wieland & Roseen Chem Ber 48 1117 1913, Voriskova Collect Czech Chem Commun 12 607 1947, Bülow Chem Ber 57 1431 1924, Campbell et al. J Chem Soc 404 1938, Morley J Chem Soc 4008 1952, Beilstein 23 I 59, 23 II 234, 23 III/IV 1658, 23/8 V 395.]
