Globular and Fibrous proteins

• What are the features of Globular Proteins?

  Globular Proteins:

  • Spherical in shape
  • Soluble > Hydrophilic - R groups on the outside allot them to form hydrogen bonds with H2O
  • Very specific shape's
  • Hydrophobic R groups point inwards away from water
  • Reactive
  • Wide range of amino acids
• What are features of Fibrous Proteins?

  Fibrous Proteins:

  • Forms a rope like structure
  • They are structural proteins (Strong)
  • They have a regular repeating structure - Few amino acids
• What are the feature of Hemoglobin?

  Hemoglobin:

  • Quaternary Structure - 4 polypeptide chains, (2 Alpha 2 Beta chains)
  • Prosthetic groups (non-proteins) - They contain Fe 2+ > Red
  • Hemoglobin is a conjugated protein
  • Globular
• What are the features of Hemoglobin?

  Hemoglobin:

  • Quaternary Structure - 4 polypeptide chains, (2 Alpha 2 Beta chains)
  • Prosthetic groups (non-proteins) - They contain Fe 2+ > Red
  • Hemoglobin is a conjugated protein
  • Globular

  
• What are the features of Insulin?

  Insulin:

  • Quaternary Structure - 2 polypeptides > Held together by disulfide bridges, between cysteine amino acids
  • Globular Protein
  • Soluble - Hydrophobic pointing inwards to avoid H2O > Hydrophilic R groups on the outside to form hydrogen bonds with H2O
• What are the features of Insulin?

  Insulin:

  • Quaternary Structure - 2 polypeptides > Held together by disulfide bridges, between cysteine amino acids
  • Globular Protein
  • Soluble - Hydrophobic pointing inwards to avoid H2O > Hydrophilic R groups on the outside to form hydrogen bonds with H2O

  
• What are the features of don't?

  Pepsin:

  • Globular protein
  • Digests proteins in the stomach > Works at pH 2
  • Many acidic R groups (don't accept H ions)
  • Very few basic R groups

  
• What are the features of Collagen?

  Collagen:

  • Quaternary Structure - 3 polypeptide chains
  • Insoluble > Many hydrophobic R groups on the outside
  • Strong/flexible
  • It has a regular repeating structure > Has very few amino acids
  • Fibrous protein

  
• What are the features of Keratin?

  Keratin:

  • Lots of cysteine > Many disulfide bridges hold together polypeptide chains
  • Insoluble
  • Fibrous protein
  • Found in hair, nails, and fur
• What are the features of Elastin?

  Elastin:

  • Elastic (strechting + recoil)
  • Fibrous protein
  • Found in the lungs and blood vessels