======Pepsin Digestion of Protein======


<WRAP right box>
**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
\\
**Categories:** {{$demo.categories}}
\\


**Alternative titles:** Protein Hydrolysis with Pepsin
</WRAP>

====Summary====                   
{{$demo.summary}}



====Procedure====  
  - Label six test tubes: 1, 2, 3, 4, “Boiled,” and “Water.”
  - Add 5 mL of albumin suspension to tubes 1–4.
  - Add 5 mL of distilled water to the “Water” tube.
  - Add 2 mL of pepsin solution to the “Boiled” tube and heat until boiling, then cool.
  - Add 3 drops of dilute hydrochloric acid to tubes 2, 3, and 4; add 3 drops of distilled water to tube 1.
  - Warm all tubes in a 40°C water bath, including the boiled pepsin.
  - Add 1 mL of warm water to tube 2, 1 mL of boiled pepsin to tube 4, and 1 mL of warm pepsin to tubes 1 and 3.
  - Incubate for 6 minutes, then remove tubes and observe changes in cloudiness.
  - Record and compare results.



====Links==== 
Proteolytic Enzymes | How Protein is Digested By Pepsin | Proteolytic Enzyme | ENGLISH - Solution- Pharmacy: 
{{youtube>ejsHX7SvyzM?}}\\


📄 BIO LAB: Enzyme Eggsploration - Southern Biological: [[https://www.southernbiological.com/content/BIO_P_BIOC_Y11%2612_1.pdf?srsltid=AfmBOoq6ZxpNR3f7B-kxrIHtypuXJwgnL7BtQSil0QPq_vdVYSXVBNpl]]\\


====Variations====
  * Test different enzymes (e.g., trypsin) on the albumin suspension.
  * Use different protein sources (milk casein, egg white) for digestion comparison.
  * Alter pH conditions (neutral, alkaline) to study enzyme activity across pH ranges.



====Safety Precautions====
  * Wear lab coat, gloves, and safety glasses at all times.
  * Handle hydrochloric acid with care; it is corrosive.
  * Use caution with hot equipment (Bunsen burner, boiling solutions).
  * Do not consume any of the materials used.
  * Wash hands and sterilize work surfaces before and after the experiment.
  * Dispose of enzyme and protein solutions according to laboratory waste guidelines.




====Questions to Consider====
  * Why does albumin appear cloudy before digestion? (Albumin proteins are insoluble; digestion breaks them into soluble peptides and amino acids.)
  * Why does the boiled pepsin fail to digest albumin? (Boiling denatures the enzyme, preventing it from functioning.)
  * Why is hydrochloric acid included in some tubes? (It simulates stomach acidity and provides optimal pH for pepsin activity.)
  * What does the comparison between tubes 1 and 3 show? (Pepsin can function without acid but is much more efficient in acidic conditions.)
  * What does tube 2 show about the role of acid alone? (Acid without pepsin does not digest albumin, so both enzyme and pH are required.)