Cytochrome c reductase, also known as NADPH-cytochrome c reductase or cytochrome P450 reductase (EC 1.6.2.4), is a flavoprotein enzyme localized primarily in the endoplasmic reticulum (ER) membrane. It plays a pivotal role in electron transfer by shuttling electrons from NADPH to cytochrome P450 enzymes and other oxygenases involved in xenobiotic metabolism, steroid biosynthesis, and detoxification processes. Due to its central function and ER localization, NADPH-cytochrome c reductase serves as a valuable biomarker for ER content and function, as well as for assessing cellular responses to drugs, environmental toxins, and metabolic changes.

Principle of the Cytochrome c Reductase Assay Kit

The Cytochrome c Reductase Assay Kit quantitatively measures the enzymatic activity of NADPH-cytochrome c reductase based on a colorimetric reaction. The assay monitors the reduction of cytochrome c, a small heme protein, by NADPH-cytochrome c reductase in the presence of NADPH. The reduction of cytochrome c leads to a distinct increase in absorbance at 550 nm, which can be continuously measured over time using a spectrophotometer or microplate reader. The rate of absorbance increase directly correlates with the enzyme activity in the sample.

Key Features

• Versatile Sample Compatibility: Suitable for mammalian tissues (liver, kidney, brain, spleen, heart), cultured cell lines (HeLa, HepG2, Jurkat), and yeast species (Pichia pastoris, Saccharomyces cerevisiae).
• Sensitive and Quantitative: Detects NADPH-cytochrome c reductase activity with high sensitivity, enabling detection from small sample volumes.
• Rapid and Convenient: Assay completion within 30 minutes to 1 hour with straightforward "load and read" protocol.
• Flexible Format: Compatible with cuvette-based spectrophotometers and microplate readers (96- or 384-well plates).
• Specificity Controls: Includes cytochrome c oxidase inhibitors (e.g., potassium cyanide) to distinguish reductase activity from other cytochrome c interactions.

Applications

• Endoplasmic Reticulum Marker: Used to quantify ER content during subcellular fractionation and isolation procedures.
• Xenobiotic Metabolism Studies: Monitoring enzyme induction or inhibition in response to drugs, environmental pollutants, or dietary components.
• Toxicology and Pharmacology: Assessment of hepatic microsomal function and cytochrome P450 system activity.
• Ecological and Nutritional Biomarkers: Evaluation of environmental pollution impact and dietary lipid uptake through enzyme activity changes.
• Basic Research: Investigations into ER physiology, enzyme regulation, and electron transport mechanisms.

The Cytochrome c Reductase Assay Kit offers a robust, sensitive, and user-friendly method for measuring NADPH-cytochrome c reductase activity in diverse biological samples. By enabling quantitative assessment of this key ER enzyme, the kit supports research in mitochondrial and ER function, drug metabolism, toxicology, and environmental biology. Its adaptability to various sample types and assay formats makes it an essential tool for both basic and applied biomedical sciences. Assay kits enable rapid, reproducible assessments, supporting biomarker discovery and therapeutic development.