The University of North Carolina at Charlotte

Deprotonated Amines

• At pH 7, an amine is expected to be protonated rather than deprotonated.

• Deprotonated amines are typically found at high pH levels (e.g. pH 9 and above).

pH and Protonation

• Understanding pH:

  • Lower pH indicates a higher concentration of protons (H+ ions).

  • High pH indicates fewer protons, leading to deprotonation of some groups.

• At pH 9, carboxylic acids are not protonated due to lower proton concentration in basic conditions.

Memorizing Amino Acids

• Recognize amino acid names and their one-letter codes (e.g., Valine = V, Glutamic acid = E).

• Important to distinguish structural changes involving substitution of amino acids in proteins.

Amino Acid Structure

• Use of wedges and dashes in 3D depictions showing different orientations of amino acid side chains.

• The alpha amino acid structure consists of an amino group, carboxyl group, hydrogen, and an R group.

Plasma Proteins Overview

• Average plasma protein concentration is about 80 grams per liter.

• Five classes of plasma proteins:

  • Albumin (55%): Responsible for transporting ions, fatty acids, and bilirubin, also involved in maintaining osmotic pressure.

  • Alpha Globulins: Include glycoproteins and lipoproteins (e.g. Prothrombin involved in coagulation).

  • Beta Globulins: Mainly lipoproteins including LDL (Low-Density Lipoproteins).

  • Gamma Globulins: Mainly antibodies produced by B-lymphocytes.

Structure-Function Relationship

• Emphasize that protein shape determines its function.

• Denaturation disrupts protein function and can occur through heat, pH changes, and various chemicals.

Denaturation of Proteins

• Denatured proteins can be caused by:

  • Heat (e.g., cooking eggs)

  • Changes in pH affecting ionic bonds and hydrogen bonding.

  • Detergents that disrupt hydrophobic interactions.

  • Heavy metals that interact with charged groups in proteins.

  • Mechanical agitation disrupting structural integrity.

Essential Amino Acids

• There are nine essential amino acids that must be ingested:

  • Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Tryptophan, Valine, Threonine, and Histidine.

• Importance of combining proteins for vegetarians to ensure intake of all necessary amino acids.

Enzyme Overview

• Enzymes are biological catalysts (typically proteins) that speed up reactions without being consumed in the process.

• Enzymes can require cofactors and coenzymes, which may include metals or vitamins.

• Different classes of enzymes are categorized based on their specific functions like oxidoreductases, transferases, hydrolases, and lyases.

Enzyme Classifications

• Oxidoreductases: Involved in redox reactions (e.g., NADH formation).

• Transferases: Transfer functional groups (e.g., phosphate transfer).

• Hydrolases: Cleave bonds by adding water.

• Lyases: Create or remove double bonds in substrates.

Practical Applications

• Consider structural stability in biological systems and medical implications (e.g., fever impacts protein structure leading to potential health issues).

• Understand experimental methods (e.g., SDS-PAGE) to analyze protein characteristics.

Conclusion

• Study and understand amino acid structure, classifications of proteins, and enzyme functions to excel in biochemistry.

• Recognize that the disruption of protein structure is a key concept impacting many physiological and biochemical processes.