Methoxy-PMS (1-Methoxy PMS)

Methoxy-PMS (1-Methoxy PMS) is a synthetic electron transfer agent widely used in biochemical analyses, such as the detection of dehydrogenase activity. As a redox mediator, it promotes electron transfer between NAD(P)H and tetrazolium salts to generate detectable formazan products. Methoxy-PMS ( C₁₄H₁₃N₂O₄S) is a methoxy-substituted derivative of phenazine methosulfate (PMS)^[1]. The methoxy group on its phenazine ring significantly enhances its stability and solubility, improves its photostability and water solubility, and makes it suitable for long-term enzyme reactions, high-throughput screening, and efficient redox cycling in vitro experiments^[2]. The low membrane permeability of Methoxy-PMS ensures that Methoxy-PMS acts only on extracellular redox reactions, offering a precise tool for the study of extracellular dehydrogenases^{[3, 4]}.

In vitro, Methoxy-PMS (3.3mg/mL) has been used in chemiluminescence (CL) assays for tetrahydrobiopterin (BH4), with a high sensitivity (detection limit of 10⁻⁸mol/L) and specificity for BH4^[5]. Methoxy-PMS (0.55mM) has also been employed to measure NAD⁺ and NADH levels in plant cells. Acting as an electron carrier, Methoxy-PMS promotes the redox reactions of NAD⁺ and NADH, generating reactive oxygen species (H₂O₂) that subsequently react with MTT to produce a detectable purple color^[6]. In cellular experiments, Methoxy-PMS (0.5μM to 10μM) has been found to inhibit PANoptosis induced by lipopolysaccharide (LPS) in macrophages. It can also suppress the production of mitochondrial reactive oxygen species (mtROS) and the oxidation of mitochondrial DNA (mtDNA) ^[7].

In vivo, Methoxy-PMS (10mg/kg) was administered intraperitoneally to a mouse model of hemophagocytic lymphohistiocytosis (HLH) induced by LPS for two consecutive days. Methoxy-PMS significantly alleviated tissue damage caused by HLH, reduced the levels of pro-inflammatory cytokines in the serum, and decreased the levels of liver and kidney injury markers (ALT, AST, creatinine, and BUN)^[7].

References:
[1] De Niz M, Eziefula AC, Othieno L, et al. Tools for mass screening of G6PD deficiency: validation of the WST8/1-methoxy-PMS enzymatic assay in Uganda. Malar J. 2013 Jun 19;12:210.
[2] Nakamura S, Arimura K, Ogawa K, et al. Use of 1-methoxy-5-methylphenazinium methyl sulfate (1-methoxyPMS) in the assay of some enzymes of diagnostic importance. Clin Chim Acta. 1980 Feb 28;101(2-3):321-6.
[3] Berridge MV, Tan AS. Cell-surface NAD(P)H-oxidase: relationship to trans-plasma membrane NADH-oxidoreductase and a potential source of circulating NADH-oxidase. Antioxid Redox Signal. 2000 Summer;2(2):277-88.
[4] Berridge MV, Tan AS. High-capacity redox control at the plasma membrane of mammalian cells: trans-membrane, cell surface, and serum NADH-oxidases. Antioxid Redox Signal. 2000 Summer;2(2):231-42.
[5] Arakawa H, Masuda K, Tajima N, et al. Chemiluminescence assay for tetrahydrobiopterin based on the generation of hydrogen peroxide using isoluminol-microperoxidase in the presence of 1-methoxy PMS. Luminescence. 2007 May-Jun;22(3):245-50.
[6] Awasthi JP, Saha B, Koyama H, et al. Quantitative Analysis of Redox Pool (NAD + , NADH Content) in Plant Samples Under Aluminum Stress. Bio Protoc. 2022 Jun 20;12(12):e4444.
[7] Shi FL, Li Q, Xu R, et al. Blocking reverse electron transfer-mediated mitochondrial DNA oxidation rescues cells from PANoptosis. Acta Pharmacol Sin. 2024 Mar;45(3):594-608.

Methoxy-PMS (1-Methoxy PMS)是一种合成电子传递体，广泛用于脱氢酶活性检测等生化分析。其作为氧化还原介体，促进NAD(P)H与四唑盐之间的电子转移以生成可检测的甲臜产物^[1]。Methoxy-PMS（C₁₄H₁₃N₂O₄S）是吩嗪硫酸甲酯（PMS）的甲氧基修饰衍生物，其吩嗪环上的甲氧基显著提升了稳定性和溶解度，增强了光稳定性及水溶性，使其适用于长时间酶反应、高通量筛选以及体外实验中的高效氧化还原循环^[2]。Methoxy-PMS的低膜通透性确保其仅作用于细胞外氧化还原反应，为细胞外脱氢酶研究提供精准工具^{[3, 4]}。

体外实验中，Methoxy-PMS（3.3mg/mL）被用于检测四氢生物蝶呤（BH4）的化学发光（CL）分析中，该方法具有高灵敏度（检测限为10^-8mol/L），并且对BH4具有特异性^[5]。Methoxy-PMS（0.55mM）被用于测定植物细胞中的NAD⁺和NADH含量，Methoxy-PMS作为电子载体，促进NAD⁺和NADH的氧化还原反应，生成活性氧（H₂O₂），进而与MTT反应生成可检测的紫色^[6]。

在体内实验中，Methoxy-PMS（10mg/kg）腹腔注射LPS诱导的噬血细胞性淋巴组织细胞增多症（HLH）小鼠模型，连续两天，Methoxy-PMS能够显著减轻HLH引起的组织损伤，降低血清中促炎细胞因子的水平，并减少肝肾损伤标志物（ALT、AST、肌酐和BUN）的水平^[7]。