Proteins

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Proteins part 1
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Proteins

• Our third big biomolecule
• Review
• the carbohydrate base unit is the _____________
• the lipid base unit is the ________________ (for
  the hydrolyzable ones anyway!)

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Proteins

• gt50 of the dry weight of the body
• 100,000 compounds
• Types of proteins
• Catalytic
• Transport
• Regulatory
• Structural
• Contractile
• Protective
• Storage

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Protein unit the amino acid

• Amino acids
• 20 required by mammals
• 10 essential must be from diet
• Four categories
• Nonpolar neutral
• Polar neutral
• Polar acidic
• Polar basic
• Natural amino acids are ____stereochemistry!

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Practice drawing Glycine Valine Cystei
ne
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Amino acids in solution

• Zwitterions
• pI and pH

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Peptides chains of amino acids

• 1 amino acid 1 amino acid 1 dipeptide
• 1 a.a. 1 a.a. 1 a.a. 1 tripeptide
• Oligopeptide
• Polypeptide
• Proteins

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Formation of the peptide bond
dipeptide
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Peptide sequences

• Name from N terminal to C terminal using three
  letter abbreviations
• gly-cys-ala
• Direction matters !!
• gly-cys-ala is different from ala-cys-gly
• Possible constitutional isomers for a given
  number of different amino acids n!

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Amino acid exercise

• Three groups draw out your share of the
  ß-endorphin, met-enkephalin, and leu-enkephalin
  amino acid sequence
• Draw from left to right, N-terminus to
  C-terminus, your amino acids on notecards using
  colored stickers
• Link the notecards together, constructing correct
  peptide bonds.
• Overall charge at physiological pH______

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Extra credit exercise (5 pts)