Estimation of Protein Concentration

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Title : Experiment 2- Estimation of protein concentration

Objectives :

1. To prepare a standard curve of absorbance versus protein concentration by using Bovine Serum Albumin (BSA).

2. To determine BSA concentration in two sample solutions.

3. To determine protein concentration in apple juice.

Materials :

Bradford Reagent, bovine serum albumin, apple juice sample, test tubes, cuvette, micropipette, tips.

Procedure :

As stated in Biological Science Practical Manual from page 11 to page 12.

Results :

Part 1: Preparation of standard curve of BSA

Table 3.1 Absorbance of BSA with different concentration

Tube | BSA 10µg/ml (µl) |

| Distilled water (µl) | Bradford reagent (µg/ml) | Concentration of BSA (µg/ml) | Absorbance at 595nm |

1 | 0 | 2000 | 500 | 0.00 | 0.000 |

2 | 100 | 1900 | 500 | 0.40 | 0.022 |

3 | 200 | 1800 | 500 | 0.80 | 0.037 |

4 | 300 | 1700 | 500 | 1.20 | 0.067 |

5 | 400 | 1600 | 500 | 1.60 | 0.089 |

6 | 500 | 1500 | 500 | 2.00 | 0.116 |

7 | 700 | 1300 | 500 | 2.80 | 0.183 |

8 | 900 | 1100 | 500 | 3.60 | 0.197 |

By using the formula, M1V1 = M2V2,

M1= Initial concentration of BSA

V1 = Volume of BSA

M2= Concentration of diluted BSA

V2 = Volume of diluted BSA

Tube 1 Tube 5

(10)(0) = M2 (2500) (10)(0) = M2 (2500)

M2 = 0 g/ml M2 = 1.60 g/ml

Tube 2 Tube 6

(10)(100) = M2 (2500) (10)(100) = M2 (2500)

M2 = 0.40 g/ml M2 = 2.00 g/ml

Tube 3 Tube 7

(10)(200) = M2 (2500) (10)(200) = M2 (2500)

M2= 0.80 g/ml M2= 2.80 g/ml

Tube 4 Tube 8

(10)(300) = M2 (2500) (10)(300) = M2 (2500)

M2 = 1.20 g/ml M2= 3.60 g/ml

Part 2: Determination of BSA concentration in two sample solutions &

Part 3: Determination of protein concentration of an apple juice

Table 3.2 Absorbance of sample solution A, B and C

Sample | Sample solution (µl) | Distilled water (µl) |...