Proteins

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Proteins

• Protein functions include
• 1. enzyme catalysts
• 2. defense
• 3. transport
• 4. support
• 5. motion
• 6. regulation
• 7. storage

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• Polymers of amino acids provide primary protein
  structure.
• -peptide bonds form between adjacent amino acids

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Proteins

• Protein structure (continued)
• -tertiary structure folded shape of the
  polypeptide chain
• -quaternary structure interactions between
  multiple polypeptide subunits
• Protein folding is aided by chaperone proteins.

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Proteins
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Proteins
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Enzymes

• Enzymes molecules that catalyze reactions in
  living cells most are proteins
• Enzymes interact with substrates.
• substrate molecule that will undergo a reaction
• active site region of the enzyme that binds to
  the substrate
• Binding of an enzyme to a substrate causes the
  enzyme to change shape, producing a better
  induced fit between the molecules.

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Inhibitors are molecules that bind to an enzyme
to decrease enzyme activity. -competitive
inhibitors compete with the substrate for binding
to the same active site -noncompetitive
inhibitors bind to sites other than the enzymes
active site
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Biochemical pathways are often regulated by
feedback inhibition in which the end product of
the pathway is an allosteric inhibitor of an
earlier enzyme in the pathway.
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Proteins
Denaturation is a change in the shape of a
protein, usually causing loss of function. -may
involve complete unfolding -caused by changes in
the proteins environment -pH -temperature -
salt concentration
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Proteins