Protein chemistry lecture 3 Flashcards
Overall shape
Globular proteins contain a spherical shape with polar interactions on the surface and nonpolar aromatic interactions on the inside of the sphere when flooded with water cause insoluble groups to fold inward which and bind to other proteins creating it’s circular folded shape.
Structure is maintained throughout evolution
Many different types of proteins coming from a variety of different species contain very different protein sequences from one another but have similar structural conformation as this is the only aspect that is conserved throughout evolution.
Partially folded conformations in proteins
Some proteins contain part of the molecule structured and another part unstructured.
Mammalian milk
This is a globular protein where 4 different types of proteins are connected together through ca bridges while 80% of the globule consists of water.
Polyelectrolytes
certain amino acids on a polypeptide chain are + charged while others are - charged. . All amino acids have a charge but only acidic side chains contain a + charge when the pH is low and basic side chains have a - charge when the pH is high. The polypeptide chain is completely charged at the isoelectric point where the charges cancel each other out.
Impact of surface charge on protein activity
Proteins can interact with certain solutes and fail to interact with others depending on the pH and the charges the AA’s have based on the charged solute that is present.
How protein conformations are formed
Their nonpolar side chains are pushed out by water causing them to fold and interact with other parts of the protein that are also nonpolar through noncovalent interactions.
Denaturation
- Heat
- Shear stress
- Chemical agents
-alchols
-fatty acids
-detergents - Loss of biological functions
-structure
-enzymes gone
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