Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

3. Amino Acids

Isoelectric Point

Biochemistry

3. Amino Acids

Isoelectric Point

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Multiple Choice

Draw the structure of Leu and determine its pI. pK _a1 = 9.6. pK_a2 = 2.4.
a. 7.59
b. 6.0
c. 3.91
d. 5.5

7.59

6.0

3.91

5.5

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Verified step by step guidance

Identify the structure of leucine (Leu), which is an amino acid with the chemical formula C6H13NO2. It has a central carbon (alpha carbon) bonded to an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and an isobutyl side chain (CH2-CH-(CH3)2).

Understand that the isoelectric point (pI) of an amino acid is the pH at which the molecule carries no net electric charge. For amino acids without ionizable side chains, the pI is the average of the pKa values of the amino and carboxyl groups.

Given the pKa values: pKa1 (carboxyl group) = 2.4 and pKa2 (amino group) = 9.6, calculate the pI by averaging these two pKa values. The formula for pI is: pI = (pKa1 + pKa2) / 2.

Substitute the given pKa values into the formula: pI = (2.4 + 9.6) / 2.

Calculate the average to find the pI, which will give you the isoelectric point of leucine.