Principle of Assay
The Membrane and Cytosol Protein Extraction Kit provides a simple and efficient method for isolating membrane and cytosolic protein fractions from cultured cells and tissue samples. The kit enables extraction of membrane proteins not only from the plasma membrane, but also from intracellular organelles including mitochondria, endoplasmic reticulum, and Golgi apparatus. Cells are disrupted by controlled homogenization, followed by low-speed centrifugation to remove nuclei and unbroken cell debris. The resulting supernatant is then subjected to high-speed centrifugation to separate cytosolic proteins from membrane-containing pellets. Membrane proteins are subsequently solubilized using a dedicated membrane protein extraction reagent. The complete fractionation procedure can be completed in approximately 90 minutes. Extracted proteins are suitable for downstream applications such as SDS-PAGE, Western blotting, enzyme activity assays, and related analyses. The membrane extraction reagent contains protease and phosphatase inhibitors, including EDTA, making it unsuitable for assays requiring active proteases or phosphatases, while remaining compatible with analysis of protein phosphorylation states. The kit supports up to 100 samples, with reagent volumes adjustable according to sample input.
