Detailed Notes on Protein Sample Preparation and Components

Sample Preparation Process

• Dyes and Reagents Used:
• Laemmli dye (2001):
  • It is often used in protein electrophoresis.
  • Bromophenol blue is one component, aiding in tracking during gel runs.
• Sodium Dodecyl Sulfate (SDS):
  • Volume used: 140 μl.
  • It serves as a detergent for denaturing proteins.
• Beta Mercaptoethanol:
  • This is a reducing agent that breaks disulfide bonds in proteins, aiding in their linearization.
• Glycerol:
  • Used to increase the density of the sample, ensuring proper loading into wells.

Sample Components

• **Different Molecules in Milk: **
• Xanthine Oxidase: An enzyme involved in purine metabolism found in milk.
• Lactalbumin: A type of whey protein beneficial for various biological functions.
• Lactoglobulin: Another major whey protein known for its role in stabilization.
• Casein:
  • This is the main protein found in milk, responsible for its white color and main component of cheese.
  • Divided into fractions (e.g., micelles).
• Milk Fat Globule & Membrane:
  • Composed of triglycerides surrounded by a phospholipid membrane.
• Glostrum: A lesser-known fraction obtained from milk, potentially used for specialized research.

Sample Processing Steps

1. Sample Preparation:

• Prepare the sample with a 1:1 dilution of dye and sample.

1. Spin the Sample:

• Centrifuge for separation.

1. Heat Treatment:

• Heat the sample for 5 minutes to denature proteins.

1. Centrifuge Again:

• Spin the sample post-heating to ensure complete separation.

1. Vortex:

• Mix thoroughly to ensure homogeneity.

1. Final Spin:

• Perform one last centrifuge to stabilize the sample.

1. Icing the Sample:

• Ice the sample to maintain protein structure before proceeding with analyses.