(FINAL) CC1 LEC L1.3 Proteins

Enzymes

Classification by Protein Function

• __________: Act as biological catalysts to speed up chemical reactions (e.g., Transaminases like ALT/AST).

Hormones

Classification by Protein Function

• __________: Chemical messengers that regulate the activity of specific target cells or organs.

Transport Proteins

Classification by Protein Function

• __________: Facilitate the movement of ions and macromolecules across biologic membranes or through the blood (e.g., Hemoglobin for O2, Albumin for various analytes).

Immunoglobulins

Classification by Protein Function

• __________: Proteins produced by B-cells (specifically plasma cells) that mediate the immune response by identifying and neutralizing pathogens.

Structural Proteins

Classification by Protein Function

• __________: Fibrous proteins that provide the physical framework for cells and tissues (e.g., Collagen, Elastin, Keratin).

Storage Proteins

Classification by Protein Function

• __________: Serve as reserves for metal ions and amino acids. Ferritin is the primary example, storing iron for later use.

Energy Source

Classification by Protein Function

• __________: Plasma proteins can serve as a reserve source of energy during states of nutritional deficiency.

Osmotic Force

Classification by Protein Function

• __________: Maintains the distribution of water between the intravascular and extravascular compartments (Oncotic pressure). Albumin is the primary protein responsible for this.

Hemostasis

Classification by Protein Function

• __________: Proteins involved in the coagulation cascade to prevent blood loss (e.g., Fibrinogen and other clotting factors).

Acid-Base Balance

Classification by Protein Function

• __________: Act as buffers to help maintain a stable blood pH by binding or releasing hydrogen ions.

Simple Proteins

Classification by Protein Structure

• Composition: Contain peptide chains composed only of amino acids.

• Physical Forms:

  • Globular: Compact, folded, and water-soluble. Often function as hormones, enzymes, or transport proteins.

  • Fibrous: Long, thread-like, and insoluble. Primarily serve structural roles (e.g., Collagen).

Globular proteins

Classification by Protein Structure: Simple Proteins

• __________: Compact, folded, and water-soluble. Often function as hormones, enzymes, or transport proteins.

Fibrous proteins

Classification by Protein Structure: Simple Proteins

• __________: Long, thread-like, and insoluble. Primarily serve structural roles (e.g., Collagen).

Conjugated Proteins

Classification by Protein Structure

• These consist of a protein (the apoprotein) joined to a non-protein prosthetic group. The entire functional unit is called a holoprotein.

Metalloproteins

Classification by Protein Structure: Conjugated Proteins

• __________:

  • Metal ions attached: Ferritin (Iron), Ceruloplasmin (Copper).

  • Complex metal groups: Hemoglobin (contains the Heme group), Flavoproteins.

Lipoproteins

Classification by Protein Structure: Conjugated Proteins

• __________:

  • Lipids attached: These transport cholesterol and triglycerides through the blood.

  • Examples: HDL, LDL, VLDL.

Mucoproteins (Proteoglycans)

Classification by Protein Structure: Conjugated Proteins

• __________:

  • High carbohydrate content: Typically >40% carbohydrate.

  • Example: Mucin.

Glycoproteins

Classification by Protein Structure: Conjugated Proteins

• __________:

  • Moderate carbohydrate content: Typically 10%–40% carbohydrate.

  • Examples: Haptoglobin and alpha-1 antitrypsin.

Nucleoproteins

Classification by Protein Structure: Conjugated Proteins

• __________:

  • Nucleic acids attached: Protein complexes bound to DNA or RNA.

  • Example: Chromatin (DNA + Histones).