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**Summary of Plant Protein Extraction Method**
This protocol outlines a reliable method for extracting proteins from plant tissues. The procedure is suitable for SDS-PAGE analysis using vertical electrophoresis systems.
1. **Preparation of Extraction Buffer:**
Based on the sample weight (typically 1 g of tissue is mixed with 3.5 mL of extraction buffer), prepare the solution on ice. Adjust the volume if needed depending on the material type.
2. **Sample Grinding:**
Place the plant tissue in a mortar and grind it thoroughly with liquid nitrogen to ensure complete homogenization. After grinding, transfer the sample into the pre-chilled extraction buffer and let it stand on ice for 3–4 hours to allow protein solubilization.
3. **Centrifugation:**
Centrifuge the mixture at 8,000 rpm for 40 minutes at 4°C or at 11,100 rpm for 20 minutes at 4°C, depending on the centrifuge available.
4. **Collection of Supernatant:**
Carefully collect the supernatant, which contains the extracted proteins, and proceed with sample preparation for SDS-PAGE.
**Extraction Buffer Composition (for 300 mL):**
- 1 M Tris-HCl (pH 8.0) – 45 mL
- Glycerol – 75 mL
- Polyvinylpyrrolidone (PVP) – 6 g
This method ensures high-quality protein extraction, making it ideal for subsequent gel electrophoresis and western blotting analyses. Always work on ice to maintain protein integrity and avoid degradation.
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